Maxillofacial prosthetics theory and practice 2011

MAXILLOFACIAL PROSTHETICSTHEORY AND PRACTICE

Mostafa FayadAssistant Lecturer of Removable Prosthodontic

Faculty Of Dental MedicineAl-Azhar University

Cairo- Egypt

2010

1st ed

Table of contents

Subjects1 intro Maxillofacial Prosthetics

2 Cleft Lip and Palate

3 mandibular defects

4 Maxillofacial Splints

5 Maxillofacial Stents

6 Radiation

7 Trismus

8 Immediate Denture

9 Snoring

10 Total and Partial Glossectomy

11 Extraoral Maxillofacial Prosthesis

12 Speech

13 Retention of Maxillofacial Prosthesis

Scope of Maxillofacial Prosthetics

Maxillofacial prosthetics is the art and science of anatomic, functional and

cosmetic reconstruction of missing or defective parts of the maxilla, mandible and/or face

by using a non living substitutes.

Maxillofacial prosthetics is the branch of Prosthodontics concerned with the

restoration and or replacement of intra-oral and associated facial structures by artificial

substitutes.

The structures may be missing or mutilated as a result of surgery, trauma, and congenital

or developmental defects.

Maxillofacial Prosthesis: any prosthesis used to replace part or all of any

stomatognathic and/or craniofacial structure.

Objectives of maxillofacial prosthetics

The most important objectives of maxillofacial prosthetics and rehabilitation include:

1 -Restoration of esthetics or cosmetic appearance of the patient.

2- Restoration of function and speech.

3- Protection of tissues.

4- Therapeutic or healing effect.

5- Psychologic therapy.

Types of maxillofacial deformities

1- Congenital : as cleft palate, cleft lip, facial cleft and missing ear.

2- Acquired: as accidents, surgery and pathology.

3- Developmental: as prognathism and retrognathism.

Classification of maxillofacial restorations according to its sits

1- Intra-oral restorations: e.g. obturators, stents and splints.

2- Extra-oral restorations: e.g. radium shield and restoration of missing eye, nose or ear.

3 - Combined intra-oral and extra-oral restoration.

4- Cranial and facial restorations:

a. cranial onlays and inlays used in cranioplasty to compensate for lost cranial

bone.

b. Intra- mandibular implants: Used to support or retain a restoration replacing

missing part of mandibular bone.

The maxillofacial team

The maxillofacial prothetist serves as a member of a team for planning rehabilitative

treatment for patients with maxillofacial defects.

These maxillofacial team including:-

1- Plastic surgeon.

2- Speech therapist.

3- Dental specialists:-

a- Prosthodontist.

b- Orthodontist.

c- Oral surgeon.

d- Dental technician.

4- Radiotherapist.

5- E.N.T (Ear, Nose and Throat) specialist.

6- Physical specialist.

7- The psychiatrist.

Cleft Lip and Palate

Mostafa Fayad 1

Cleft Lip and Palate prostheses

Normal Anatomy:

a- Maxilla is a pyramidal-shaped bone. It consists of a body which forms the mid face and four processes. These processes are the frontal and zygomatic processes upwards and the alveolar and palatine processes downwards. The alveolar process carries the anterior and posterior teeth. The palatine process forms the anterior two thirds of the hard palate. The maxilla has several distinct anatomical areas.

The nasal spine is the anterior projection of the maxilla and alveolus.

The alveolar process of the maxilla surrounds the palate and houses the teeth.

a- The palate is composed of the maxillary and palatine bony plates. The palatine process of maxillary bone forms the anterior two thirds of the palate and the horizontal maxillary plate of palatine bone constitutes the posterior third of the hard palate. They are both divided into right and left by a longitudinal midline suture.

The anterior part of the palate is formed of the anterior alveolar process carrying the anterior teeth and the premaxilla.

Blood vessels and nerves exit from the incisive foramen anteriorly and the greater and lesser palatine foramina postero-laterally.

The incisive canal is located posterior to the incisors, and transmits the lesser palatine artery, one of the distal branches of the internal maxillary artery.

Posteriorly and laterally along the palate is the greater palatine foramina, which transmit the greater palatatine artery, a branch of the internal maxillary artery.

The palate itself is formed from the maxilla, the horizontal process of the palatine bone and the pterygoid plates.

c- The soft palate is the unossified part of the palate. It attaches to the posterior rim of the hard palate. Medially, a posterior extension, the uvula or the velum extends downwards and acts as a valve for the pharyngeal cavity.

The soft palate contains a series of muscles , numerous minor salivary glands and some lymphatic tissues and a dense network of elastic fibers which together with the muscles of the pharynx form a sphincter that opens and closes the orifice between the nasal cavities superiorly and the oro-pharyngeal cavity inferiorly.


Mostafa Fayad 2

The soft palate attaches to the posterior portion of the hard palate and interdigitates with the lateral pharyngeal wall via several muscular attachments. From the naso-pharyngeal to the oral cavity surface, the muscles of the soft palate consist of:

- the palatopharyngeus, - the salpingopharyngeus,

- the levator and tensor palatini, - the muscular uvula,

- the palatoglossus - the superior constrictor muscle.

The tensor veli palatini tenses the palate, but is not believed to play a major role in palatal elevation.

The levator veli palatini is responsible for palatal elevation. Also may pull the lateral pharyngeal walls down and back.

The salpingopharyngeus is a consistently small muscle with probable minimal effects upon palatal and tubal function.

The superior constrictor muscle is the primary sphincter of the pharyngeal phase (Velopharyngeal Closure) of swallowing and is responsible for preventing regurgitation into the nasopharynx (velopharyngeal insufficiency, VPI) .

Muscle Origin Insertion Action

levator veli palatini

temporal bone, Eustachian tube

palatine aponeurosis elevates soft palate

tensor veli palatinimedial pterygoid plate of the sphenoid bone

palatine aponeurosis tension of the soft palate

musculus uvulae hard palate palatine aponeurosis

palato glossus palatine aponeurosis tongueraising the back part of the tongue

palato pharyngeuspalatine aponeurosis and hard palate

Upper border of thyroid cartilage (blends with constrictor fibers)

pulls pharynx and larynx

http://en.wikipedia.org/wiki/Levator_veli_palatini

http://en.wikipedia.org/wiki/Levator_veli_palatini

http://en.wikipedia.org/wiki/Temporal_bone

http://en.wikipedia.org/wiki/Eustachian_tube

http://en.wikipedia.org/wiki/Palatine_aponeurosis

http://en.wikipedia.org/wiki/Soft_palate

http://en.wikipedia.org/wiki/Tensor_veli_palatini_muscle


http://en.wikipedia.org/wiki/Tension_(mechanics)

http://en.wikipedia.org/wiki/Soft_palate

http://en.wikipedia.org/wiki/Musculus_uvulae

http://en.wikipedia.org/wiki/Hard_palate


http://en.wikipedia.org/wiki/Palatoglossus_muscle


http://en.wikipedia.org/wiki/Tongue

http://en.wikipedia.org/wiki/Tongue

http://en.wikipedia.org/wiki/Palatopharyngeus_muscle


http://en.wikipedia.org/wiki/Hard_palate

http://en.wikipedia.org/wiki/Thyroid_cartilage

http://en.wikipedia.org/wiki/Thyroid_cartilage

http://en.wikipedia.org/wiki/Pharynx

http://en.wikipedia.org/wiki/Larynx


Mostafa Fayad 3

Structures of the Hard Palate:

-Premaxilla

- Incisive Foramen

-Palatine Processes

- Posterior Nasal Spine

Structures of the Soft Palate

-Velum (Soft Palate itself)

- Muscular Uvula

The Pharynx:

The pharynx is a simple, funnel shaped tube wide at the head and narrow at esophageal end. The pharynx has three muscles superior, middle and inferior constrictors. The action of the pharynx is complex but basically it contracts from side to side and its posterior surface moves forwards. It is capable of local contractions at various levels, which are mainly used in speech, and also peristaltic type of contractions which are employed during swallowing.

The shape and action of the soft palate and pharynx in speech and swallowing are different

Dark line illustrates position of soft palate and posterior pharyngeal wall during speech. Dotted line illustrate position of both when swallowing. Note marked shift of pharyngeal wall in swallowing position.


Mostafa Fayad 4

Palato (velo) pharyngeal mechanism (Palato (Velo) Pharyngeal Sphincter)

The velopharyngeal mechanism is a coordinated valve formed by the muscles of the soft palate and pharynx.

Muscles forming the velo-pharyngeal sphincter

Muscles forming the velo-pharyngeal region are, (fig.3):

1-Muscles forming the palate, these are:

-Levator veli palatini muscle -Tensor veli palatini muscle

-Palato glossus muscle -Palato pharyngus muscle

-Uvula muscle, which is the intrinsic muscle of the velum

2-Muscles forming the pharynx, these are:

-Superior constrictor muscle -Salpingo pharynges muscle

-Palato pharyngus muscle which has two portions, the pharyngo palatal

portion and the thyro-palatal portion

The levator veli palatini muscle and the superior constrictor muscles play the dominant role in velo-pharyngeal mechanism especially during closure of the nasal cavity. The levator veli palatini muscle is a long muscle and provides a wide range of movement necessary in moving the velum from the relaxed rest position to a fully elevated position

Palato (Velo) Pharyngeal mechanism

The velum acquires three positions to perform the valve action required during swallowing and speech, these are:

1-The relaxed position of the velum (uvula)

This is the relaxed position of the velum. It is required during normal breathing. The velum is dropped downwards to keep the oro pharynx and naso pharynx opened to allow for both oral and nasal breathing.


Mostafa Fayad 5

2-Closure of the nasal cavity

Velo pharyngeal mechanism is required for closure of the nasal cavity during swallowing and for production of letters produced in the oral cavity. This mechanism is achieved as follows:

-The middle third of the velum curves upwards and backwards in an attempt to contact the posterior wall of the pharynx at or above the level of the plane of the palate at the level of the atlas vertebra. This is done by the action of the levator veli palatini muscle. This is aided by the contracted state of both the tensor veli palatine muscle and the uvulae muscle that adds bulk to the nasal surface of the velum.

-However, this pull of the velum is not enough to achieve adequate closure between soft palate and pharynx.

For this reason the pharynx shares in palato pharyngeal mechanism by:

*Movement of the posterior wall of the pharynx forwards. This is done by the action of the superior constrictor muscle aided by the pharyngo palatalportion of the palato pharyngus muscle.

*Movement of the lateral walls of the pharynx medially to close the last gap between thelateral aspect of soft palate and lateral walls of pharynx. This is done by the action of the salpingo pharynges muscle.

*The posterior pharyngeal muscles contracts strongly and produces a bunch-up forming a prominent ridge or pad called “Ridge of Passavant”. This helps to approximate the soft palate and pharynx,

Ridge of Passavant

The ridge of Passavant is a horizontal roll of muscles on the posterior wall of the pharynx forming a bunching-up of the posterior pharyngeal wall. It is present at the level of the palate which corresponds to the level of the atlas vertebra. It is usually more evident in patients with soft palate defects as a compensating mechanism to aid in speech and swallowing. It also serves as a guide for placement of soft palate prostheses


Mostafa Fayad 6

3-Closure of the oral cavity

Velo pharyngeal mechanism is required for closure of the oral cavity. This is required to permit exit of air through the nasal cavity during sucking and pronunciation of sounds as “M” and Ng as in sing. This mechanism is achieved as follows:

-The thyro-palatal portion of the palato pharyngus muscle pulls the soft palate downward towards the tongue.

-The tensor veli palatini muscle flattens the dome-shape of the soft palate.

-The tongue is forced upward and backward.

-The palato glossus muscle contracts and completes the palate tongue approximation.

It function as follows:

1-Velopharyngeal closure: It is required for normal deglutition and the production of some speech sounds such as plosives (e.g. P&D). This closure occurs by the following:

a-The middle of the soft palate curves upwards an backwards as an attempt to contact the posterior wall of the pharynx. This action is done by the levator and tensor palatini muscles.

b-The posterior wall of the pharynx moves forward by the action of the superior constrictor and the palatopharyngeous muscles forming the ridge of passavant. This ridge is a horizontal roll of tissues on the posterior wall of the pharynx corresponds to level of the atlas vertebra. It occurs during speech and swallowing and serves as a guide for placement of soft palate prosthesis.

c-The lateral walls of the pharynx move medially by the action of the salpino pharyngeous muscle.

2-Velopharyngeal opening:

This occurs during normal breathing and for pronunciation of vowels and nasal consonants in a varying degrees. It is a relaxed position; the soft palate drops downward to keep the oropharynx and nasopharynx opened.


Mostafa Fayad 7

Velopharyngeal insufficiency:

Palato pharyngeal insufficiency is a condition characterized by abnormal anatomy of the palate in the form of absence, short length or cleft in the tissues of the soft palate. This could be congenital, or due to acquired causes as resection of soft palate or lateral pharyngeal wall. This condition results in inability to perform palato pharyngeal mechanism.

Prosthetic rehabilitation is achieved by palato-pharyngeal obturator (speech bulb) or by meatle obturator.

Nasal sounds

Velopharyngeal incompetence:

Palato pharyngeal incompetence is a condition characterized by normal anatomy but ineffective or absent motor function (tissues are functionally impaired) resulting in impaired palato pharyngeal mechanism. This usually results due to neurological disorders as poliomyelitis affecting oro-pharyngeal structures through affection of any of the nerves of the pharyngeal plexus which includes fibers from the IX, X and XI cranial nerves. It could also be due to diseases as multiple sclerosis or tumors, or due to traumatic head injuries. Oral sounds

Palato pharyngeal incompetence usually results in speech disorders in the form of

hyper nasality or reduced speech intelligibility.

Palato pharyngeal incompetence is diagnosed by easily lifting the soft palate by a tongue

depressor, by nasal endoscopy or by airflow pressure measurements.

Prosthetic rehabilitation is achieved by a palatal lift device.

Development of Palate

The development of the palate begins in the fifth week and is completed in the twelfth week intrauterine. It develops from:

1-The primary palate is derived from the median nasal process and the maxillary process and gives rise to:


Mostafa Fayad 8

a-The upper lip.

b-The premaxilla; the part of the hard palate in front of the incisive foramen

c- The anterior part of the alveolar process and the incisors.

2-The secondary palate: is derived from two horizontal lateral palatine (nasal) processes or palatine shelves. It gives rise to:

a-Hard palate posterior to the incisive foramen.

b-Soft plate.

At about the end of the eighth gestational week, the shelves elevate, make contact, and fuse with each other above the tongue Failure of union at any stage will result in a cleft palate and or lip.

Because the secondary palate arises from the lateral palatine processes which fuse in the midline, vascular, lymphatic, and neural elements are divided at the midline. This phenomenon explains why unilateral palatal and paranasal sinus tumors rarely demonstrate contralateral lymphatic spread. The midline also serves as an effective anatomic barrier for resistance of local tumor extension and often serves as the medial surgical margin in resection of palatal and paranasal sinus tumors.

Palatal cleft development

The union of the primary palate, the secondary palate and the nasal septum begins at the meeting point of the premaxilla and the two lateral palatine processes (incisive foramen). From this point of meeting union progress anteriorly and posteriorly in a Y –shaped suture. Anteriorly, to form the premaxilla, anterior alveolar ridge and upper lip and posteriorly to form hard and soft palate.

Congenital clefts occur during embryological growth due to arrest of development and failure of fusion between the embryonic processes.

Incidence of cleft lip and palate

Cleft deformities of the palate are among the most common congenital malformations. A cleft palate can be diagnosed as early as the 17th week of gestation by means of ultra-sonography. Although many studies exist, the exact environmental and genetic factors that play a role are still largely unknown. However, the following can be concluded:


Mostafa Fayad 9

1- The incidence of clefting has a racial differences. However, the average incidence rate is one in every 700 born has some form of clefting.

2-Unilateral clefts are more common than bilateral clefts of the lip and palate.

3-Left side cleft forms 70% of unilateral clefts.

4-The incidence of clefts in males is twice that in females.

Development of the palate, shown from beneath (left) and in coronal section (right).(a) 7th week; (b) late 8th week; (c) 10 weeks. Swellings on the medial aspect of the maxillae growdownwards either side of the tongue (a), then swing medially to form horizontal palatal shelves (b);these fuse with each other and with the nasal septum by breakdown of the apposed epithelial seams(c). e, eye; es, epithelial seam; hps, horizontal palatal shelf; mn, medial nasal swelling; mx,maxillary process; nc, nasal conchae; ns, nasal septum; pp, primary palate; r, rugae; uv, uvula; vps,vertical palatal shelf


Mostafa Fayad 10


Definition : A cleft palate may be defined as a lack of continuity of the roof of the mouth. It may be congenital or acquired.

A] Congenital cleft palate

It is a lack of continuity of the roof of the mouth though the whole or part of its length in the form of fissure extending anteroposteriorly.

Etiology : Congenital cleft palate results from lack of fusion of embryological processes which would normally unite during the 6th to 10th weeks of embryonic development. The exact cause of the clefts is unknown but it may be:

1- Abnormal position of the embryo,2- Pressure from the amniotic fluid,3- Failure of the tongue to drop,4- Persistence of epithelium at the junction of the two palatal halves.

Hereditary and environmental factors influence the induction of the cleft palate:

1-Hereditary: There is widespread agreement that a hereditary bases exsists in about 20 to 30 % of all cases of clefts of lip and palate.

2- Environmental factors and teratogenic agents (predisposing factors):

Nutritional deficiency or cortisone administration has never been proved to be teratogenic in humans. The principal environmental causes are:

1- Oxygen deprivation and glucose deprivation .2- Nutritional deficiency e.g. Vitamin A and riboflavin deficiency.3- Infectious diseases of the mother during pregnancy e.g. Acute virus infections as

German measles..4- Cortisone therapy and hormonal disturbance as in pituitary dysfunction.5- Radiotherpy and excessive X-ray exposure to the mother’s pelvic area during early

pregnancy. 6- Chemical irritation e.g. hypervitaminosis A and hypoxia to the pregnant mother.7- Stress and anxiety during the first trimester of pregnancy, since these conditions result

in excessive production of adrenal hormons (cortisone) which has been shown to induce clefting in mice.


Mostafa Fayad 11

The present of environmental factors together with the hereditary background may increase the incedance of cleft lip and palate.

Types of Congenital cleft palate

Clefts may be isolated malformations or may be a part of a syndrome. Clefts of the

palate, alveolus and lip (CLAP) are:

Syndromic types are by definition associated with other malformations (At last

count, more than 300 syndromes were associated with CLAP).

Syndromic etiologies include:

- Single gene transmission such as trisomies.

- Teratogenic causes such as fetal alcohol syndrome; or

- Environmental causes such as maternal diabetes mellitus

Non-syndromic CLAP is a diagnosis of exclusion, and is considered to be of

multifactorial inheritance with known predicted rates of recurrence.

Syndrome: major malformations which appear unrelated but are frequently found

to have a common etiology.

Sequence: anomalies occur together the primary anomaly causes the first to

happen.

e.g., Pierre Robin Sequence - failure of mandible to grow in utero causes a u-shaped cleft

of the soft and hard palate but not the alveolar ridge.

Classification of cleft palate:

Victor Veau’ s classification

It is generally accepted and give more details of cleft palate.

class I. Clefts involving soft palate only.

Class II. Clefts involving soft and hard palates up to incisive foramen.

Class III. Clefts of soft and hard palates, right forwards through alveolar ridge and continues into lip on one side.

Class IV. Same as Class III only associated with bilateral hare- lip.


Mostafa Fayad 12

Veau’s classification of cleft palate.

Olin's classification:

Group I. Cleft lip only: unilaterally or bilaterally with nasal deformity.

Group II. Cleft palate only: part of the soft palate, or the entire soft and hard palate maybe involved.

Group III. Clefts of lip and palate involve the alveolar ridge. Patient may have unilateral or bilateral clefts

Group IV. Clefts of the lip and alveolar ridge not involve the palate (Rare occurrence).

Harkin's classification:

Patients are classified according to the degree of the cleft into:

Bifid uvula.

Cleft of the soft palate.

Cleft of soft and hard palate extending through the palatal bones.

Cleft of the soft and hard palates extending to the incisive foremen.

Cleft of the soft and hard palates extending through the alveolar process and lip on one side.

Davis classification: (1922) (Not used now) Classification depends on the extent of cleft

Group 1: all clefts of the lip

Group 2: All posterior alveolar clefts.

Group 3: complete cleft of alveolar ridge, palate & lip.

Stark's classification (1958) (The most widely used today).


Mostafa Fayad 13

Disabilities associated by the presence of cleft palate

The basic disability of a cleft palate results from inability to close well the nasopharynx from the oropharynx. Patients with a cleft lip or palate have numerous associated problems, such as the following:

1. Esthetic problem: due to

- Basic anatomic deformity - Deficient facial growth

Abnormal appearance of the child occurs due to the presence of labial cleft and facial deformity due to improper or early surgical repair of palatal cleft. Trauma to the growth center of bone during surgery leads to reduction of the forward growth and lateral dimension of the maxilla.

2-Improper mastication: The masticatory function is impaired because babies cannot suck due to lack of negative pressure, food escape through the nasal cavity and the presence of missing teeth and malocclusion.

3-Swallowing: Swallowing is impaired when cleft occurs in both hard and soft palate. The baby should be placed in upright position and a special nipple is used during feeding.

4. Dental problems

-Missing, malformed, and supernumerary teeth -Malocclusion

5. Speech problems (see speech & Palato (velo) pharyngeal mechanism)

-Velopharyngeal incompetence - Secondary articulation disorders

6. Otologic problems

- Eustachian tube dysfunction - Chronic ear disease

- Hearing loss

7-General health: The general health of the child is affected due to inadequate nutrition and mouth breathing.

8-Psychological problems: Children with clefts have difficulty in adjusting with society. They may withdraw or turn aggressive.

9- Additional congenital anomalies.


Mostafa Fayad 14

Diagnosis and examination of cleft palate:

The patient should be examined by all maxillofacial specialists.

Maxillofacial team

The management of patients with acquired or congenital defects involves the cooperation of the following team members:

1- Plastic surgeon: The role of plastic surgeon is important in treatment planning and surgical reconstruction of deformities.

2-Prosthodontist: Prosthodontic treatment may be required in inoperable cases and in case of failed surgery.

3-Speech therapist: The role of speech therapist is to correct defective speech caused by the palatal defects.

4-Orthodontist: The orthodontist treat malocclusion associated with cleft lip and palate.

5-Psychologist: Help the patient to accept the problem, and to improve patient’s attitude and cooperation in the course of treatment.

6-Social worker: Discusses the problem with parents, educate them about the problem and guide the patient for his future life.

7-Dental technician: Construct the prosthetic appliance.

The following procedures facilitate the diagnosis:

1- General case history including all information about the cleft and anomalies.

2- Clinical examination and photographs.

3- Construction of study cast.

4- Radiographic procedures includs full mouth x-ray, bit wings, occlusal andcephalometric x-rays.

5- Medical, surgical, speech, and psycological recording.

N.B. Study casts, photographs and radiographic data are recorded periodically to help the

dentist to study the growth and development patterns of oral-facial-cranial structures and

to observe the effects of surgical and orthopedic treatment.


Mostafa Fayad 15

Diagnosis and treatment planning are carried out through the maxillofacial team. Full consideration should be given to the following:

1-Type and width of the cleft.

2-Position and relation of the maxillary segments to each other.

3-Form of the maxillary arch and its lateral and antero-posterior dimensions.

4-Length, thickness and mobility of the soft palate.

5-Perforations remaining in the hard and soft palate and labial sulcus after surgery.

6-Posterior and lateral pharyngeal wall activities size of naso-pharynx.

7-Floating premaxilla.

8-Number of missing teeth in line of cleft, malformed and malposed teeth and partially erupted teeth.

9-Constricted maxilla.

10-Condition of tonsils and adenoids.

11-Growth and development of the child, mental attitude and general health must also be considered.

12-Speech articulation of the patient, his voice quality and hearing acuity.

Treatment planning:

Any child born with cleft palate should be examined by the plastic surgeon, orthodontist, the prosthetist and the speech therapist, in consultation and a combined plan of treatment is formed .

I-Pre-surgical treatment phase

This phase starts at birth and may continue till surgical repair is performed. Treatment in this phase includes:

-Psychological support to the parents provided by the social worker and the


Mostafa Fayad 16

nurse to encourage parents to correctly care for their child.

-Teaching parents how to care for and clean the defect.

-Teaching parents how to feed the infant to ensure proper nutrition necessary for growth and development. Ensuring that feeding requires longer time and patience compared to normal infants. Feeding devices could be selected from among the wide variety present in the market.

Infants with cleft lip most often feed normally only slight milk leakage which can be overcome by using a bottle with broad base nipple to seal the defect during feeding. They can also be breast fed.

Infants with cleft palate are usually more difficult to feed due to their inability togenerate and maintain vacuum and loss of negative pressure required for sucking. This may cause early fatigue and improper feeding. For this reason using squeezable bottles, soft nipples with cross cut openings rather than tiny holes are recommended to allow for easier flow of nutrients. Long nipples can also be used in order to be placed posterior to the defect. Feeding spoons which are deep and with long pointed tips can also be used.

2- Surgical management of congenital cleft palate

The following should be taken into consideration:

1- Surgical closure is the treatment of choice for congenital defects.

2- Lip repair is usually performed 6-12 weeks after birth to facilitate feeding and improve

appearance if the infant’s physical health allows.

3- Repair of the cleft palate is performed after 1-4 years (usually 2 years). Early repair

of the cleft palate should be avoided to permit for the growth of the palate with narrowing

of the cleft and to permit for development of enough tissues for closure.

4- Surgical repair of the soft palate is superior to the fitting of a prosthesis. But if the cleft

is too wide and the muscular remnants poorly developed it is better to treat the cleft

entirely by prosthetic obturator.


Mostafa Fayad 17

If surgery can only produce a non-functional united soft palate, the prosthetic obturator should be performed instead of surgery because the problem of fitting an obturator in cases with repaired nonfunctional soft palate is greater than in those cases which not surgically treated.

If a pharyngoplasty has been performed, a surgical repair of pharynx should be performed before the end of the second year because the child commences to talk between the second and third years and if repair is delayed beyond this time faulty habits of speech will develop which are too difficult to eradicated.

If it is decided that surgery is unlikely to be successful the first obturator should be fitted at the end of second year.

If the cleft of hard palate is too wide it is better to cover it by obturator because surgiacal repair will certainly result in contraction of the dental arch and the orthodontic treatment will reopen the cleft.

3- Prosthetic management of congenital cleft palate

Objectives of cleft palate prosthesis:

1- Restoration of masticatory apparatus.

2- Restoration of speech.

3-Prevent foods from enter the nose and prevent nasal secretion from enter the mouth.

4- Improve the esthetics of the patient by restoring the missing part of ridge and teeth.

5- Improve psychological condition of the patient.

Indication of maxillofacial prosthesis:

Generally, surgical correction of cleft palate is better than prosthetic treatment However,

there are some situations in which a prosthsis may be the treatment of choice as:

A-In unoperated cases:

1. A wide cleft with a deficient soft palate that cannot function properly after

surgery.


Mostafa Fayad 18

2. A wide bilateral hard palate cleft. In such cases surgical repair of the soft

palate can be performed and an obturators is constructed for the hard palate.

3. Partial or complete paralysis of the soft palate remnants.

4. In patients with neuromuscular disease affecting the soft palate and pharynx

resulting in velopharyngeal incompetence.

5. Absence of the premaxilla.

6. Patients with poor general health.

7. The cleft palate may be temporarily closed with speech aid, when surgery is

delayed.

8. When orthodontic appliance (e.g. expansion appliance or appliance to correct

teeth position) is indicated.

B- In operated cases:

1-Failure of surgery to close the defect completely.

2-When the soft palate movement is inactive or completely absent or the soft

palate is short causing incompetent palatopharyngeal closure.

3-A transitional prosthesis to provide certain function, e.g. feeding appliance or

appliance to activate the soft tissues of the pharynx for function.

Contra-indications for maxillofacial prosthesis

1- Easability of surgical repair

2- Uncooperative patient and parents.

3- Uncontrolled dental caries as rampant caries.

4- Mentally retarded patient.

5- Lack of dentist who has had training in cleft palate prosthodontics.


Mostafa Fayad 19

Prosthetic devices used in management of congenital cleft palate

1-Obturators (discussed later)

An obturator is an appliance, which corrects openings in the hard palate, soft palate or both. The prosthetic treatment consists of the construction of an obturator or an artificial palate for closing the cleft and restoring the function of speech and swallowing.

2-Orthopedic treatment

Early orthopedic treatment of any patient should be underten on the basis of a joint decision of the surgeon, the orthodontist, and the prosthodontist.

The orthopedic appliances are of two types:

a- The passive or holding type.

b- The active or expansion type.

The type of appliance will be determined by the configuration of the cleft.

1- If any degree of collapse is manifested, an expansion appliance is placed.

2- If the collapse is primarily in the anterior region, a fan type of split acrylic appliance is used.

Splint acrylic appliance (Fan type) B. The cast before and after treatment .

3- If it appears that the arch is collapsed throughout its length, a straight Jack screw appliance is used

Jack screw appliance.


Mostafa Fayad 20

4- If the cleft configuration is wide or if the segments appear in an ideal relationship, a holding appliance is used. These case are operated on as soon as the holding appliance is placed.

All appliances, whether active or passive, are fabricated and inserted prior to lip closure. After the maxillary appliance has the segments is good alignment, the plastic surgeon restores lip continuity.

Expansion type prosthesis

An expansion prosthesis may be used preoperatively for complete unilateral or bilateral collapsed palate clefts. These prosthesis used to guide the maxillary segments into proper spatial relations with each other and with the mandibular arch prior to surgery. The segments can be gradually separated by an expansion prosthesis to create a space for the premaxilla or to stabilize the parts in a normal position with or without bone grafting.

In the period of expansion several successive prosthesis may be constructed considering the growth and possible eruption of the teeth.

Indications:

1-In patients having complete unilateral or bilateral collapsed cleft, to align the lateral segments of the palate before surgery.

2- To assess and diagnose the need and progress in speech that will be achieved by surgery.

The expansion prosthesis is consists of palatal portion and pharyngeal portion.

a- The palatal portion composed of two separate lateral sections covering the hard palate and united by expansion device. In the predental eruption period. The prosthesis cover the alveolar ridge and extend to the mucobuccal fold. When the teeth are erupted the prosthesis is extended to the lingual surface of the teeth and retained by wire claspe.

b- The pharyngeal portion may be constructed in some cases to improve the speech and deglutition.


Mostafa Fayad 21

3- Combined prothesis and orthodontic appliance:

In case of malposed teeth an orthodontic appliance may be combined with a prosthesis to move malposed teeth into a more favorable alignment. A speech appliance prosthesis could be designed for patient receiving full band orthodontic treatment.

Obturators used for treatment of congenital cleft palate

1- Preoperative devices for children:

- Feeding devices

- Expansion prosthesis.

2- Cleft palate prosthesis for adolescent:

Fixed pharyngeal obturator.

3- Cleft palate prosthesis for adult (definitive obturator)

I-Prosthetic rehabilitation of congenital cleft palate (in children)

1- Feeding devices:

In case of cleft lip the infant can feed normally with a bottle or breast. To prevent

milk leakage the finger is placed over the lip cleft or a broad base nipple is used.

In case of unilateral alveolar cleft the nipple should be pointed toward the

unaffected side.

For cleft palate the infant cannot suck. A syringe is used or a specially designed

bottle and nipples, while the infant in a semi-upright position. Soft nipples, crosscut

nipples, or long nipples and squeeze bottles can be used. In some cases an obturators

attached to the nipple is used.

The importance of feeding appliances:

1- Most infants with cleft lip and palate are unable to nurse from the breast

or bottle. Since normal suckling is impossible, a more upright position

of the baby, and a bottle with large hole nipple may compensate for the


Mostafa Fayad 22

slow flow of milk or fluid associated with defective suckling.

Sometimes Nasogastric tube is used for feeding.

2- The repeated pressure of the tongue on the nipple forces it upwards

against the edges of the cleft and tends to increase the width of the cleft.

All these difficult conditions make the construction of the feeding device essential to separate the oral cavity from the nasal cavity and thus , facilitate food intake and reduce irritation prior to surgical closure.

Construction:

The feeding devices consists of an acrylic plate, constructed from a low fusing compound impression.

A mass of softened compound is placed on suitable tray or on the convex surface of the spatula and mould it to the shape of block of the needed size. Then compound is inserted into the baby’ s mouth to the back of the pharynx and with light upward and forward movement, so that the edges of the cleft leaves their marks on the block.

The compound impression is taken out by moving the spatula from the front to back and then downward and forward. The impression is poured in stone and allowed to set before separation. A plate of softened wax is adapted on the lingopalatine surface of the model formed the palatine wings of the obturator. The wax is replaced by acrylic resin using the routine method of flasking, then finishing and polishing are done.

The plate can be designed to be attached to the neck of feeding bottle to cover the cleft during bottle feeding. Or the acrylic plate can be made with a wire or acrylic handle to be held by the mother to cover the cleft during breast feeding.

2-Expansion prosthesis

The expansion prosthesis (described before) may be constructed with pharyngeal portion to improve the speech and deglutition.

II-Prosthetic rehabilitation of congenital cleft palate for adolescents

Dental considerations for adult cleft patients


Mostafa Fayad 23

Oral disfigurement is not gross nowadays due to advances in the management of newborns and infants. Problems associated with rehabilitation of cleft adult or adolescent patients

-Missing or malformed incisors is the most common dental defect associated with cleft.

-High smile line exposing residual soft tissues which become unaesthetic if

bridges are to be constructed. Hence, removable partial dentures are constructed.

-Cleft alveolus that is unreconstructed by bone grafts results in movement of the two segments of maxilla which results in break of cementing cement if fixed bridges are constructed. Hence, removable partial dentures are constructed.

-Early surgeries lead to scarring which hinders growth of maxilla leading to discrepancy in size of maxilla and its relation to the mandible.

-Lack of early orthodontic treatment.

-Dental neglect and poor oral hygiene.

-Inadequate vertical dimension of occlusion.

Proper dental care, oral hygiene measures, osteotomy to reposition maxilla in a downward and forward position and interim dentures to restore vertical dimension are lines of treatment that may precede prosthetic rehabilitation.

Temporary appliances are usually constructed for adolescents till they reach complete growth. A temporary appliance is a great aid to the prosthodontist to assess and determine the best design providing an esthetics, mechanical and functional prosthesis. It is also considered an educational tool for the patient.

However, it may sometimes be required to construct metal removable partial dentures for patients between 11 and 20 years where esthetics and retention are primary demands. In this case a self-cleansing restoration with margins ending as far as possible from the gingival margin and natural teeth should be designed.

Definitive appliances are usually constructed at the age of 20 after complete growth and bone grafts if present, are mature.

Definitive appliances to obdurate clefts may be attached to a partial denture, a complete denture or an overdenture depending on the condition and number of teeth.


Mostafa Fayad 24

For partially edentulous patients with surgically repaired clefts removable partial dentures with similar designs as non-cleft patients are constructed. However, patients with palato pharyngeal deficiencies, the partial denture will be extended to the pharyngeal cavity as a speech aid which may in turn exerts a long lever arm especially in free end saddle cases. Thus, the design of partial denture needs to be altered to provide additional direct and indirect retention.

For completely edentulous patients, several problems may arise during complete denture construction as the maxilla of these patients tends to be smaller in size compared to the normal sized mandible. This is usually due to reduced forward and downward growth of maxilla. These problems are:

1-Reduced bony support due to small maxilla.

2-Increased inter arch space.

3-Lack of adequate denture support and stability.

4-Inadequate retention due to ineffective posterior palatal seal due to scar

issue if surgery was previously performed.

5-Scarring of lip tissues which may affect anterior border seal and exerts a

backward push on the denture, thus affecting denture retention.

Appliances for habilitation of congenital cleft palate (for adolescents):

1-Fixed pharyngeal obturator (speech aid)

The fixed pharyngeal obturator is an extension of a denture projecting into the pharynx to the level of the anterior arch of the atlas bone or Passavant’ s ridge. The obturator is shaped so that it can be gripped by the pharyngeal walls.

They are temporary appliances usually constructed for adolescents (between 11-20 years) till they reach complete growth.

Normal lateral growth of the palatal bones necessitates replacement of this prosthesis occasionally. Intermittent revisions of the obturator section can assist in maintenance of palatopharyngeal closure.


Mostafa Fayad 25

It is a space filling prosthesis, designed to be held in the lower region of the nasopharynx to compensate for the tissue deficiency. It acts as a core against which palatopharyngeal musculature can form a seal.

N.B. Passavant's ridge is a horizontal ridge or cushion around the lateral and posterior walls of the pharynx at the horizontal level of the hard palate coinside with the anterior tubercle of the atlas vertebra. It is a compensatory factor associated with cleft palate that help in reducing the diameter of palatopharyngeal orifice.

The passavant’s ridge is present in few cases and used as a reference point to place the pharyngeal section of the fixed pharyngeal obturator.

Objectives:

The prosthesis must establish a competent naso-oral separation to satisfy the following objectives:

1-Socially acceptable speech.

The prosthesis must help the patient to acquire normal speech pattern. For reasonable speech articulation and resonance there must be adequate dental relation together with adequate oronasal separation.

2-Restoration of masticating apparatus.

Help in mastication and increases the efficiency of chewing and confine the food material in the oral cavity. Help in deglutition and prevent the seepage of fluids to the nasal cavity during the act of swallowing.

3-Prevent the seepage of nasal secretion into the oral cavity.

4-Facial esthetics and dental harmony.

Improve the esthetics of the patient.

Restoring the missing, malposed and improve the articulation of the teeth to establish dental esthetics.

5-Improve psychological condition of the patient.


Mostafa Fayad 26

Fixed pharyngeal obturator requirements:

1- The prosthesis must be designed to suit the patient regarding his oral and facial condition, masticatory function, and speech.

2- The prosthesis must preserve the remaining structures wrong design of the maxillary portion will result in premature loss of the hard and soft tissues and further complicating prosthetic habilitation.

3- The prosthesis requires greater retention and support. In adult cases, crowing and splinting of the abutment teeth increases retention and, support.

4- Closed vertical dimension in more suitable in the cleft palate patients.

5- Minimum weight should be kept. The material used should be easily repaired and altered.

6- Soft tissue pressure in the velar and naso–pharyngeal areas by the appliance must be avoided.

7- The prosthesis must not be displaced by velum, lateral and posterior pharyngeal wall muscle activities or tongue movement during swallowing and speech production.

8- Pharyngeal section should be properly placed. The superior surface of the pharyngeal section must be at the level of the palatal plane.

Preparation of the patient for prosthetic treatment:

The oral cavity should be prepared before the construction of the speech aid prosthesis as follow:

1-Decayed teeth are preferably restored with full coverage to prevent recurrence of decay and to shape the teeth in the desirable form to support and retain the speech aid in position.

2-Every tooth in the cleft palate patient should be saved to avoid problems of retention.

3-Teeth needing extraction or other surgical treatment should be preferably done before the construction of the speech aid.


Mostafa Fayad 27

4-Orthodontic treatment to expand the arch or approximate the two segments and correct malposed teeth are done at this stage if possible.

5-Gingivectomy for partially erupted teeth is recommended to expose the clinical crown to be used for retention.

Sections of speech aid: The speech aid consists of three sections; palatomaxillary section, palatovelar section and pharyngeal section.

a-The palatomaxillary section:It covers the cleft of the hard palate, and may be constructed in the form of partial or complete denture. In general the number of retainers is increased.

b- The palatovelar section or tailpiece: It supplements the palatal cleft and must remain in lateral contact with the soft palatal muscles during function or rest.

c- The pharyngeal section (speech bulb): It extends posteriorly into the pharyngeal cavity to be surrounded by the sphincteric action of the pharyngeal muscles during swallowing and speech.

Sections of speech and (a) Palatomaxillary, (b) Palatovelar, ( c) Pharyngeal.

Construction:

Preliminary impression:

Prior to taking the impression the undercuts in the palatal cleft is packed with vaseline gauze. An alginate impression is taken in a suitable stock tray and cast is poured.

Final impression:

An acrylic special tray is constructed and the final impression is taken with rubber base or alginate impression material. The deep undercuts in the hard palatal cleft should be packed with vaseline gauze prior to taking impression.


Mostafa Fayad 28

Recording jaw relation:

If the patient is edentulous the upper denture should has an upward extension that engages undercuts in the cleft to help retention.

If the patient is dentulous the working model is surveyed and the cleft in the hard palate filled in with plaster of paris to reproduce the contour of a normal palate. On this prepared model a record block is constructed. Jaw relation is recorded in the usual manner and the casts are articulated.

The artificial teeth are set in positions demanded by appearance and occlusion.

At the try-in the usual points are checked and a wire loop made of German silver or stainless steel is bent and attached with sticky wax to the base of the trial denture. This loop should be adjusted by bending and altering its position in the wax until it lie along the center of the cleft of the soft palate, without contact with its remnants or with the posterior pharyngeal wall when a prolonged “ah” is sounded. If the loop is made of German silver wire, it will be more easily adjusted than if made of stainless steel.

In some cases where difficulty to the wearing of the denture is anticipated it is desirable to leave the wire loop off the denture and allowing the patient to wear the denture for few weeks until it is quite comfortable. The wire loop may than be added to the denture with cold cure resin to avoid the induce of extra strains in the acrylic by a second processing.

Denture with wire loop

After the denture has been completed and fitted, a tailpiece must be made and attached to the back edge of the denture and positioned at a level just below the soft palate when assumes fully relaxation. If the tailpiece is positioned at higher level, discomfort and pressure sores will occure when the soft palate relaxes. If on the other hand the level of the tailpiece is much below that assumed by the relaxed soft palate, then it will cause discomfort by obstructing the movements of the tongue.

For locating the plane of the tailpiece a piece of pink base plate wax is attached to the back edge of the denture with sticky wax, this wax should be wide and long enough to cross the soft palate into the pharynx.

The denture carrying the wax is then inserted into the mouth and the patient is instructed to relax and breath through the nose. After few minutes the wax will be


Mostafa Fayad 29

moulded by the relaxed soft palate above and the tongue below to conform to the plane and contour of the relaxed palate. The denture is removed and the wax is chilled thoroughly. The denture is then replaced into the mouth and the plane of wax in relation to the relaxed soft palate is checked with the mouth open.

If there is any appearance of the wax supporting the soft palate, the shaping technique as previously described should be repeated. When the plane and contour of the wax is satisfactory, a plaster model is cast under the palatal side of the wax and extending under the denture to enable it to be located. After the plaster set, the wax is removed, and replaced by thin mix of cold cure resin. The back of the denture should be roughened to ensure a firm union between the denture and the cold cure resin.

The velar section can also be constructed after few weeks from using the denture by attaching a piece of base plate, which act as a tray, to the posterior part of the upper denture with suitable relief for the zinc oxide impression paste. During taking the impression the patient should hold his head in a vertical position to prevent the escape of the material into the naso-pharynx.

Construction of speech bulb

A piece of soft modeling compund is added on the wire loop that attached to the end of the velar section. The denture with the soft compound is inserted into the mouth and the patient is requested to swallow, say “ah” move his head up and down and then from side to side while the compound is still soft. A drink of warm water or hot tea will facilitate swallowing. The denture is removed, cleaned, dried and the compound is inspected and reheated then reinserted in the mouth and the patient is asked to do the same previously described movements using stick compound to correct the impression section by section .

Impression wax softened in water bath maintained at 51 - 64 C painted over the green compound with a brush. The denture carrying the compound and wax is inserted to the patient s mouth and the same previously described movements are performed. The prosthesis is removed and reinseted several times with gradual adjustment to the speech bulb until a satisfactory functional impression is made. The impression wax has the advantage that it can stay soft in the mouth for relatively long period for better regestration of the functional movement. The size of the bulb should be adjusted until the patient can breath clearly through the nose and produce acceptable nasal sounds. If the patient is sensitive enough to produce a gag reflex, the speech bulb should be made underextended using self curing resin, allowing the patient to wear the denture for few


Mostafa Fayad 30

weeks until he is accustomed to the underextended bulb, then the final impression of the speech bulb is taken.

The black gutta-percha can also be used to make impression for the speech bulb. This material can be fully adjusted to fit the movements of the pharynx and palatal remnants before being processed in acrylic resin. The black gutta-percha has the advantage of remaining soft enough to be moulded by the pharyngeal musculature for about 5 minutes after each heating, while at the same time remaining sufficiently viscous to support its own weight. It is therefore deformed by muscular pressure and then retaines the shape impressed on it by that pressure. The final details should be register by zinc oxide paste. Speech bulb moulded in gutta-percha

A special large flask is used for curing the tailpiece into clear acrylic, resine.

If the speech bulb is not too large and the deture is well retained, the speech bulb can be made of solid acrylic. If however, the speech bulb is large ,or if the denture is poorly retained due to there being only a few nature teeth present in the upper jaw or if it is a full upper denture, then the speech bulb should be made hollow to reduce the weight of the appliance.

Correction of the speech bulb

If the speech bulb need correction, the tissue conditioning or functional material is applied to the bulb portion and the prosthesis is inserted into the mouth. The patient can use the speech aid at home under normal conditions. The advantage of this is that at home the patient can make the normal phisiologic movement without stress. While in the clinic the patients are usually exaggerate there movement which may lead to inaccurate impression.

when the palate is cleft a problem of how a fixed obturator which can fit the cleft in both the functions of speaking and swallowing will developed.

The solution of this problem may include the following. In relation to the function of an obturator it is suggested that :-

- The patient must learn new speech habits.


Mostafa Fayad 31

- The gripping of the bulb during swallowing is a basic principle which must be mastered

- The action in producing the palatal consonants is horizontal instead of vertical and involves the gripping of the pulb as in swallowing.

The plane of location of the obturator must be in the plane of action of the palatopharyngeal sphincter or bulge of passavant so the individual can gripping it with his ring or sphincter mechanism and squeezing the remnants of the soft palate against it.

In practice an obturator is shaped by luting a piece of softened gutta-percha to a wire loop or tail piece extending from the posterior border of the denture along the midline of the cleft into the pharynx. The gutta-percha is then shaped by the muscles as they function.

Special Obturator Prostheses:

1- Hinged pharyngeal obturator

2- The palatal lift prosthesis

3- The meatal obturator

1- Movable (Hinged) pharyngeal obturator

The hinged pharyngeal obturator is similar to the speech aid, it consists of three sections. However the velar portion is attached to the posterior border of the denture by a hinge and its lateral borders are shaped to be gripped be the ruminants of the soft palate and moved with them. The pharyngeal section is activated by lateral pharyngeal musculature.

Delabarre (1820) emphasized the importance of the normal soft palatal movement during biologic and activities and constructed a prosthesis a soft rubber velar as in the more simple hinged type obturator. Although these prosthesis were mobile under influence of the cleft soft palate, the movement was more similar to mechanical movements than to physiologic function.


Mostafa Fayad 32

Disadvantages

a- The hinged obturator fail to achieve noraml physiologic soft palate movement.

b-The hinge is a source of weakness and frequently gets out of adjustment.

The mobile rubber prosthesis:

This prosthesis was constructed with a soft rubber velar section. The movement was more similar to mechanical movements than to normal physiologic function.

2-The Palatal Lift Prosthesis

This type of prosthesis is designed to displace the soft palate superiorly and posteriorly to assist the soft palate to close with the peripheral pharyngeal tissues.

Indications

a-Neurologic diseases as myssthenia gravis, cerebrovascular accidents, traumatic brain injuries, and bulbar poliomyelitis.

b-Injuries to the soft palate as following adenoidectomy, tonsillectomy, or maxillary

resections.

c- Postsurgical cleft palate with insufficient length and movement.

Contraindications

1- If adequate retention is not available.

2- If the palate is not displaceable.

3- Uncooperative patients.

The objective of the palatal lift prosthesis

-To displace the soft palate to the level of normal palatal elevation enabling closure by pharyngeal wall action

-In cases where the length of the soft palate is unsufficient to effect closure after maximal displacement, the addition of an obturator behined the displaced soft palate may be necessary.


Mostafa Fayad 33

This prosthesis may used as a diagnostic aid to assess the possible improvement in speech. Some clinicians believe that the use of a palatal lift on an interim basis may stimulate flaccid soft palate to increase functional activity.

A Anatomically normal but paralyzed soft palate,

B Palatal lift prosthesis in position elevating soft palate to produce palatopharyngeal closure.

A Congenital anatomic insufficiency of palatopharyngeal region,

B Palatal lift obturator in position elevating soft palate and obturating palatopharyngeal space.

The advantages of palatal lift prosthesis

a-The gag response is minimized (because of the superior position and the sustained

pressure of the lift portion against the soft palate.

b-The tongue is not changed (because of the superior position of the palatal

extension.

c- The access to the nasopharynx for the obturator (if necessary)becomes easier.

d-The lift portion of the prosthesis may be extended gradually to help patient

adaptation.

e-Useful treatment for surgically risky patients.

Construction

The impression is taken using custom tray that extended with baseplate wax to record and displace the soft palate superiorly. A suitable partial denture framework is


Mostafa Fayad 34

fabricated and verified. The retentive meshwork or wire loop is extended to cover the anterior two thirds of the soft palate. Modeling plastic is added to the retentive meshwork until the appropriate displacement of the soft palate is achieved. Then a thermoplastic wax is used to record tissue detail. If displacement of the soft palate does not achieve adequate obturation the obturator can be extended behind the deficient soft palate.

It is important to insure that the lifting force does not create soreness and the force of displacement does not have an adverse effect on the supporting dentition.

3- Meatal obturator prosthesis

Meatus obturator has extension of the posterior border of maxillary section upward and backward to close the posterior openings of the nose. It is used when there is very large cleft to reduce the resonance of the nasopharynx.

The meatal obturator establishes closure with nasal structures diagonally above the hard palate terminus. The obturator extends superiorly and slightly posteriorly from the hard palate border and separates the oral and nasal cavities at this level

There are no movable tissues in this area and closure is established against the turbinates, the residual vomer (if present) and the roof of the nasal cavity.

The position of meatal and conventional obturators in relation to palate plane.

Indications

a-This type of obturator may be indicated for patients with extensive defects of the soft palate with a very active gag reflex.

b- For edentulous patients when retention is a problem.( when horizontally extended speech aid is thought to be result in prosthesis displacement by leverage action.


Mostafa Fayad 35

A meatus obturator should be considered when the posterior extension of fixed obturator prosthesis is likely to result in prosthesis displacement. Since the vertical extension is closer to the palatal portion of the prosthesis, less torque is placed on the palatal portion, thus decreasing the tendency to dislodge.

Advantages

a- Lesser in weight comparing to the conventional obturator.

b-The downward displacement force from the obturator extension is closer to the

supporting tissues of the parent prosthesis. This result is less lever action.

Disadvantages

a- The obturator does not enable the patient to control nasal air emission because it is positioned in an area devoid of muscle function.

b-Distortions in nasal resonance occar, because the oral cavity and oral pharynx areincreased in size and the nasal cavity is proportionally reduced.

Construction

The definitive maxillary prosthesis is constructed first, and a wire loop is attached to the palatal end of the prosthesis. Modeling plastic is added to the wire loop to mold the obturator. Head, speech, and swallowing movements are unnecessary because there are no movable tissues in this area. The obturator is reduced 1mm and refined by thermoplastic wax.

Over extension should be avoided because nasal mucosa is delicate and will not withstand stress. After processing two small holes or hole approximately 5mm in diameter should be drilled through the obturator to permit nasal breathing. An alternate method is to reduce the lateral dimensions of the obturator until nasal breathing is restored.

4- Silicone retentive obturator:

Indications:

a) Congenital clefts.


Mostafa Fayad 36

b) Acquired defects.

c) More retention is required.

Material: Silicone or rubber latex.

Technique of construction.

5- Fixed Prostesis (Stabilize Premaxilla).

6- Snap-on Prosthesis:

Types:

a) with speech pulp. b) without speech pulp.

8- Unconventional speech aid prosthesis:

Two sections: Nasal portion – Denture.

9- Titanium self tapping implants:

Position: Alveolus – Ptrygoid plates.

10- Root coping (attachments) Telescopic crown with rest.

II-Prosthetic rehabilitation of congenital cleft palate for adults

Definitive obturators for adults

Definitive appliances are usually constructed at the age of 20 years, when growth and development is complete and bone graft, if present, is mature.

A definitive prosthesis is usually made for a patient whose experience with a diagnostic one has been successful and surgery is contraindicated.

Obturators are attached to a partial denture, complete denture or an overdenture.

A- Partially edentulous patients

The design of the partially edentulous patients in cleft patients is similar to partial dentures in normal patients. However, the partial denture is extended to the pharynx in


Mostafa Fayad 37

cleft patients. This extension exerts a long lever arm, which call for additional direct and indirect retainers.

In the presence of scar tissue on the palate, the borders of major connectors should follow the scar tissue rather than crossing them, with minimal beading.

The center of rotation of the partial denture.

B- Completely edentulous patients

The problems associated with completely edentulous cleft patients are:

1-The size of the maxilla is reduced due to reduced downward and forward growth of the maxilla.

2-Increased inter-arch space also occurs as a result of maxillary growth reduction.

3-Lack of adequate support, retention and stability; due to lack of adequate bony palate, lack of effective posterior palatal seal due to scarring, shallow depth of the palate and poor alveolar ridge development.

4-Scarring in labial vestibule, in case of lip closure, affects peripheral seal and denture retention.

B. Acquired palatal defects

While congenital clefts are confiend to the lines of union of the different embryonic processes of the palate, the acquired defect may occur any where in the palate. The cleft may involve the alveolar process, tuberosity, the hard palate and/or the soft palate, half the upper jaw or more. Nasal and adjacent tissues may be involved.

Causes of acquired defects

1-The commonest cause is radical surgical removal of tumors (malignant or benign) of the palate and paranasal sinuses.


Mostafa Fayad 38

2-Trauma by accidents from pencil, gunshot, severe compound comminuted fracture.

3-Pathalogical conditions, like osteomyelitis of the palatal bone, syphilis, tuberculosis and radium burns.

Disabilities associated with acquired maxillary defect

I- Function:

a-Speech: It is markedly changed after surgery by increased hypernasal speech. These patients do not require speech therapy after prosthetic treatment because they had a learned speech pattern.

b- Swallowing: Swallowing may be difficult, foods and fluids regurgitates into the nasal cavity.

II- Appearance:

Disfigurement of the face and Diplopia may occur if the surgery extends to the inferior border of the orbit.

III- Psychological Trauma:

The psychological impact of loss of part of the face is very severe on these patients.

Rehabilitation of acquired maxillary defects

I- Surgical rehabilitation:

It is the best line of treatment, but it is limited to the following cases:

1- If the defect is the result of trauma.

2- In small size defects.

3- Tumors unsusceptible to recurrence.

II- Prosthetic rehabilitation:


Mostafa Fayad 39

It is indicated in the following cases:

1-Large defects which is difficult to be corrected surgically.

2-Tumors with susceptibility to recurrence.

Phases of prosthetic treatment:-

1- Initial phase (surgical obturation):

The prosthesis should be placed at surgery or immediately thereafter. It restores and maintains oral function at reasonable levels during the post-operative period until healing is completed.

2- Second phase starts 3-4 months after surgery when the surgical site becomes stable dimensionally thus permitting construction of the definitive prosthesis.

Obturators used for treatment of aquired cleft palate

1- Immediate surgical obturator.

2- Delayed surgical obturator.

3- Definitive obturator..

1- Immediate surgical obturator:

This obturator is constructed presurgically and inserted immediatelly after surgery in the operating room. It is in the form of simple acrylic plate with retaining clasps or holes in the flanges for wiring to remaining teeth or to available bony structures.

This obturator is particularly suitable for dentulous patients requiring a partial or total maxillectomy as the remaining teeth used to help retention of the prosthesis. It must not be removed before 7-10 days after surgery.

Advantages of immediate obturator

I- Functional:


Mostafa Fayad 40

1- The prosthesis provides a matrix on which the surgical packing can be placed.

2- Permits the patient to speak and swallow more normally by reproducing normal palatal contour and by covering the defect.

3- Allows earlier removal of the nasogastric tube.

4-It can carry a skin graft or medicaments in the proper relationship to the surgical cavity.

II- Hygienic:

The prosthesis reduces oral contamination of the wound during the immediate post surgical period, reducing the incidence of local infection.

III- Psychological:

1-It decreases the psychologic impact of surgery by reproducing the contours of the lost oral structures and maintain the function.

2-It helps to reduce the hospitalization period and thus reduce the costs of hospitalization..

3- Restores the patient's self-image by reproducing the contours of the lost oral structures and allows the patient to function in social environment.

Principals relative to the design of immediate surgical obturators

1- If it is possible the surgeon should leave the posterior edge of the hard palate & tuberosity. Otherwise the soft palate will be flabby and often drop inferiorly.

2- The obturator should terminate short of the skin graft-mucosal junction. As soon as the surgical packing is removed., extension into the defect may be accomplished with tissue conditioning or interim soft lining materials.

3- The prosthesis should be simple and light in weight.

4-The prosthesis for dentulous patients should be perforated at the interproximalextension to allow the prosthesis to be wired to the teeth at the time of surgery.


Mostafa Fayad 41

5-Normal palatal contours should be reproduced to facilitate postoperative speechand deglutition.

6- A couple of wire loops is attached to the fitting surface in cases of big tumor.

7- Posterior occlusion should not be established on the defect side until the surgicalwound is well organized. If the three maxillary anterior teeth included in theresection, they may be added to the prosthesis to improve esthetics.

8- The existing complete or partial denture may be modified for use us an immediate surgical obturator. The flange at the defect should be reduced and the posterior teeth removed prior to surgery. Tissue conditioning material may be used to improve adaptation at the time of surgery.

The technique of construction

First, the abutment teeth should be surveyed and if there retentive undercuts do not appear to be adequate., tooth modification should be made, which may include re contouring. ”dimpling“ or placement of restorations.

Upper and lower alginate impressions are made in a perforated stock trays. The maxillary impression tray must be modified to allow for the size of the tumor so it should extended posteriorly with baseplate to record a significant portion of the soft palate in the impression. The patient should be placed in an upright position so that the soft palate assumes a relatively normal and relaxed position. If the patient has an active gag reflex, it is useful to use topical anesthetics and fast-setting alginate.

It is important to make an accurate impression of the vestibular depth .on the resected side so that the approximate position of the skin graft mucosal junction can be determined.

The upper and lower impressions are poured in stone and the maxillary cast is dublicated for future reference. The casts are mounted on a suitable articulator with the aid of a jaw relation record.

The surgeon and prosthodontist should discuss the surgery together and outline the proposed surgical margins on the upper cast. The lateral boundary is usually the labial and buccal reflex and the medial boundary is the midline of the palate. The questionable extensions are the anterior and posterior margins.


Mostafa Fayad 42

Try to persuade the surgeon to leave the posterior edge of the hard palate and tuberosity. It is better to encouraged the surgeon to make the anterior incision through the socket of an extracted tooth instead of between adjacent teeth.

A- Margins of proposed surgical resection are outlined on the cast. B- Teeth included in the resection are removed and cast is trimmed for fabrication of immediate surgical obturator.

The maxillary cast is altered to conform to the proposed surgical resection. Teeth on the area involved are cut away from the cast, but alveolar height is maintained. Any elevation on the cast representing the palatal swelling should be removed to give a normal palatal contour. The residual alveolar ridge is trimmed moderately on the labial and buccal surface to reduce the stress on the soft tissue closure.

If the pterygoid hamulus is removed during the maxillectomy procedure, the attachment and/or function of the tensor veli palatine, buccinator, and superior constrictor muscles can be compromised due to the medial collapse of the distolateral portion of the defect. In this case the cast should be reduced 2 to 3 mm medially.

The wire retainers are adapted and the prosthesis is waxed, invested and processed in clear acrylic resin , then finished and polished in the normal manner.

A couple of wire loops is added at the fitting surface to hold the lining material.

Clear resin is preferred because the extensions and possible pressure areas can be easily seen at surgery.

Holes are drilled in the buccal flanges when it is supposed to wire the obturator to the zygomatic arches and/or anterior nasal spine.

Prior to surgery the obturator is immersed in a disinfectant solution, the required instruments are autoclaved, and the dental material are sterilized with gas.


Mostafa Fayad 43

In most cases the obturator is easily fitted and secured. The lateral extension of the obturator should be adjusted short of the skin graft-mucosal junction to avoid pressure to this area. The lateral and anterio aspects of the obturator should be reduced until correct facial contours are abtained without creating tension during closure.

The surgical packing will accommodate for most discrepancies. However, if the surgery was more extensive than planned it is preferable to add a thick mix of soft denture liner to the obturator. If the deficiencies are modest, a thinner mix of the soft lineror tissue conditioning material is used.

In the past autopolymerizing acrylic resin or impression compound were used for major additions to the obturator at surgery. However, resin is difficult to manipulate and the free monomer has adverse effect on raw tissue surfaces. Impression compound deteriorates easily intraorally, especially if used in conjunction with tissue-conditioning materials.

If a weber-Fergusson exposure is used, the prosthesis should be inserted before closing the cheek flap then the defect is packed with gauze and the cheek flap is closed. If a transoral surgical approach is used, the defect should be packed prior to inserting the prosthesis.

Retention can be obtained in dentulous patients by wiring the prosthesis to existing teeth. In edentulous patients the obturator is wired or pinned to the alveolar ridge and zygomatic arches and /or anterior nasal spine.

After 7 to 10 days postsurgically

The prosthesis and packing are removed. The obturator is cleansed; the wire retainers and minor occlusal discrepancies are adjusted.

A new application of tissue conditioning material may be made to improve adaptation , seal and comfort.

The patient is dismissed for one week with the instruction regarding the irrigation and cleaning of the surgical defect properly.

Usually the patient is seen every 2 weeks and the tissue conditioning material changed to suite for tissue contracture. It is better to remove and


Mostafa Fayad 44

change all of the lining material to reduce bacterial contamination and mucosal irritation.

2-Delayed surgical obturator:

It is an alternative to immediate surgical obturator that placed 7 to 10 days postsurgically. It is the treatment of choice for edentulous patients with extensive surgical defect.

The technique of construction

I- Tray selection and modification:-

1- The surgical packing is removed.

2- A soft metal stock tray with short flanges and clearance of 1/4 inch exists in all dimensions is selected.

3- In the area of the defect, much of the flange may be removed or bent medially.

4- All flanges are covered with peripheral beading wax and additional wax is added in the area of the defect to provide support for the impression material.

II- Impression making:

Major medial undercuts and other sensitive areas should be blocked-out with Vaseline gauze. The gauze is used to limit the extension of the impression material into the defect. An impression is carried out using alginate impression material in the modified ray. The impression should be removed gently to avoid pain during removal.

IV- Prosthesis fabrication:

In dentulous patients: -

1-The prosthesis will be fabricated as the immediate obturator, from acrylic resin base with wrought wire clasp.

2-Anterior teeth, if missing, can be included for esthetic reason.

3- Posterior occlusion should be avoided to reduce the movement of the acrylic resin extension against tissue, but as healing proceeds, posterior occlusal ramps


Mostafa Fayad 45

can be established with addition of self-curing resin to help the patient to retain the prosthesis in position.

4- The prosthesis is delivered and adjusted using pressure indicating paste and articulating paper. If it fits well and is well retained, it is not necessary to add temporary lining material.

In edentulous patient: -

It is preferable to use the patient own maxillary denture as a delayed surgical obturator, with the following modifications: -

1- The labial and/or buccal flanges of the denture are shortened on the side of defect.

2- The existing denture is inspected to insure that it well adequately obturates the surgical defect.

3- Self-cure acrylic resin may be added to the denture to cover the margin of resection on the soft palate.

4- After adjustment of the denture the obturator should be lined with relining material.

Instructions to the patient:

1- The patient should not remove the obturator at nights. The obturator remains in place except for brief periods while cleaning the defect and the prosthesis. If the obturator is removed for extended periods of time, the patient may have difficulty reinserting it.

2-Patients are instructed to use a soft toothbrush and hand soap to clean the prosthesis. Effervescent types of denture cleansers should be avoided, as they will cause blistering of the soft lining materials of the post-surgical prosthesis.

3- The patient should visit the prosthodontist monthly for evaluation of the fitting of the prosthesis and cleaning of the maxillary sinus.

3-Definitive obturator:

It is constructed 3-4 months after surgery. The timing will very depending on many factors. The timing will vary depending on:


Mostafa Fayad 46

1- The size of the defect.

2- The progress of healing.

3- The prognosis for the tumor.

4- The effectiveness of the present obturator.

5- The presence or absence of teeth.

The prognosis of definitive obturator depends on (Treatment concepts):

1- Defects classification : Maxillary defects have been conveniently classified according to the defect location and its relation to the remaining teeth by Aramany, 1978.

Aramany classification of maxillary defect

2- Movement of the prosthesis: If the maxillary alveolar ridge and teeth are involved in the resection the obturator will displaced superiorly with the stress of mastication and will tend to drop without occlusal contact.

3-Tissue changes: Dimensional changes will occur specially during the first year after scar contracture. The obturator portion should be made of acrylic resin to facilitate rebasing if required.

4- Extension into the defect: The degree of extension of the prosthesis into the defect will depend on the requirements of retention, stability and support. If the remaining maxillary structures give adequate retention, stability and support, a lettel extension into the defect will be required. The presence of teeth enhances the retention, stability and


Mostafa Fayad 47

support so generally the use of the defect in edentulous patients is more extensive than dentulous patient.

5-The weight of the prosthesis: Bulky areas should be hollowed to reduce weight to avoid unnecessary stress to the teeth and supporting tissues. The hollowing is done during packing the acrylic resin, by placing a sand bag between the acrylic resin in the middle of the defect. After currying a small hole is made on the fitting surface to empty the obturator from the sand. Then the hole is closed with self cure acrylic resin.

The construction of the definitive obturator will vary with the type of resection and the presence or absence of teeth. Techniques for both edentulous and dentulouspatients with total or partial maxillactomy defects will be described

The superior surface may be closed to avoid accumulation of the nasal secretions leading to odor and added weight, or left open to decrease the weight and is easier to adjust. In the open type if secretions do tend to accumulate, a small diagonal opening may be made between the inferior-lateral floors of the obturator through to the cheek surface for drainage. If the skin graft lining the cheek surface has no secretory potential, an open top is acceptable.

6- The presence of teeth: As with all maxillofacial prostheses the presence of teeth enhances the prosthetic prognosis. The teeth will assist retention, stability, and support for the prosthesis.

7- Covering prostheses: The obturators are basically covering prostheses serving primarily to reestablish the oral-nasal partition.

1- Edentulous patient with total maxillectomy defects

With any palatal perforation, retention in the classical sense of complete denture is impossible, so that the residual palatal structures and the defect must be used more extensively to improve retention, stability and support. In most cases acceptable retention can be gained from:

1-Remaining palatal structures: The arch form and the amount of palatal shelf remaining influence the stability and support. A square or ovoid arch will exhibit relatively more palatal shelf area following a total maxillectomy.


Mostafa Fayad 48

The surgeon should be encouraged to resect only enough hard- palate to allow adequate tumor margins. Especially important is ipsi-lateral palate preservation, which will allow a tripoding effect. If the anterior alveolus can be maintained, the patient will have better facial and less contracture postoperatively.

2-Engagement of the skin graft superiolaterally above the skin graft mucosal scar band. The thick squamous epithelium of a split-thickness skin graft will resist the wear and tear applied by the obturator. Engagement of the skin graft and the scar band formed at the skin graft-mucosal junction will significantly improve retention. The scar band is flexible and will permit the prosthesis to be inserted but will tend to resist dislodging forces.

3-Extending the prosthesis along the oral surface of the soft palate

Junction of oral mucosa and skin graft lining.

4- Additional retention may be gained by extending the obturator along the nasal surface of the soft palate and or anteriorly into the nasal aperture. If the vomer was surgically removed, an undercut may exist superiorly along the medial margin. However, this is a bony undercut lined with respiratory mucose. Therefore, this area is limited for use unless a resilint material is used to engage the undercuts.

The support and stability can be improved by engagement of key portions of the defect. Stability is enhanced by engaging the superuolateral portion of the defect and the medial margin of the defect when it is lined with keratinized epithelium.

Some support can be obtained from the oral side of the skin graft-mucosal junction and from the oral surface of the soft palate.

Technique of construction

Impression technique:

The skin graft-mucosal junction

Nasa

Oral


Mostafa Fayad 49

An edentulous soft metal tray is selected and ultered according to the configuration of the remaining maxilla. The medial and anterior undercuts are blocked out with vaselineated gauze.

Adhesive is applied to the tray and alginate is mixed and loaded in the tray. Prior to seating the tray, impression material is wiped or injected into posterior and lateral undercuts. Cast is poured, and the undesirable undercuts are blocked out with wax.

shim is provided and a special tray are made from acrylic resin. Extension of the tray are verified in the mouth. Several perforations are made for escape of the impression material with at least three perforations being along the medial palatal margin.Border molding using modeling plastic is carried out initially on the unresected side to stabilize and orient the tray to the defect. The modeling plastic is relieved approximately 1 mm in all the areas. The tray and modeling plastic are painted with adhesive. Saline irrigation is performed to remove excess nasal secretions .

Elastomaric impression material is prepared and injected into desirable undercut areas and the loaded tray is seated into position. The lips and cheek are manipulated and the patient is instructed to perform eccentric mandibular movements to account for the movement of the anterior border of the ramus and the coronoid process of the mandible. After the material has set, the impression is removed with a gentle teasing action.

Obturaror should maintain contact with soft palate during elevation otherwise fluid leakage may occur.

If the anterior margin of the soft palate exhibits marked elevation during swallowing and speech, the portion of the impression that engages the superior and inferior part of the soft palate is cut away with a scalpel and a functional impression is advocated using thermoplastic wax. To reinsert the impression, it may be necessary to trim some of the impression material that has engaged undesirable undercuts.

If the patient exhibits extreme trismus, an alternative impression techniques is suggested by using the surgical obturator after making necessary adjustment. A new application of tissue conditioning material (or impression material ) is used for tacking final impression.


Mostafa Fayad 50

Recording of jaw relationship

Two methods are suggested for construction of record bases.

1- If the defect is large and stability and support are difficult to obtain with a conventional record base, the definitive base is fabricated from the master cast. This base is used in recording jaw relation and at a later time the denture teeth are added with self curing acrylic resin.

2- If stability and support are adequate, a conventional self curing acrylic base is constructed after blocking of all undercuts and the rugae area to protect the master cast.

The vertical dimension of occlusion is determined in the usual manner using wax rims on the record bases. An arbitrary face bow transfer is obtained and centric relation is recorded.

Trismus is common in patients received radiation therapy. If trismus is extreme, the vertical dimension of occlusion is reduced to allow passage of the food between the denture teeth.

Care must be taken to prevent displacement of the maxillary record base during the registration. Even in acceptable stable maxillary base, pressure on the defect side will result in superior displacement into the defect. Soft wax, zinc oxide or plaster are the material of choice for recording jaw relation.

The use of tracing devices to record centric relation are contraindicated.

Nonanatomic posterior teeth are preferred and adjusted to eliminate lateral deflective occlusal contact. The trial denture are tried in the mouth and changes are made to accommodate the esthetic desires of the patient and the prosthodontist.

Processing, delivery and follow up:

The obturator with the denture are processed in heat-cured acrylic resin. On delivery, the resin extensions into undercut areas may require considerable relief to permit seating of the parosthesis.

The superior surface of the obturator should be slightly convex and well polished. Any sharp projection on the lateral surface of the obturatot should be rounded and polished with pumice. Polishing improve cleansibility and reduce the friction between the prosthesis and soft tissue during functional movements.


Mostafa Fayad 51

If more retention in necessary, soft silicon material is used for the obturator segment to engage undercuts more profoundly.

Home care instructions are reviewed and recall appointments are arranged. Most maxillary obturator will require rebasing within the first year because of dimentional changes of the defect.

Modifications over the next years are often performed if the prosthesis becomes intolerable to the patient or a warning signs are encountered. The warning signs that the obturator is no longer functioning are, liquid reflux into the nasal cavity, change in the quality or nasality of the voice.

To obtain hollow bulb: During backing of acrylic resin a small cellophane bag filled with sand is backed within the bulb. After processing, a hole is drilled throughout the bulb and sand drained away. The opening is then closed with self-curing resin.

Superior surface of the obturator should be slightly convex and well polished to decrease friction during functional movement.

To gain better retention, soft material allows the obturator to engage the undercut in the defect more aggressively.

2- Edentulous patient with partial maxillectomy defects:

In this defects, more of the hard palate remains and thus the stability and support are increased. However, retention may be reduced. Soft silicone materials may be used to improve retention by engage bony undercuts .

Fabrication of definitive obturator for partial resections of the edentulous maxilla are similar to the prosthesis for total maxillectomy resection. However , rebasing is not necessary as frequently.

3- Dentulous patients with maxillectomy defects:


Mostafa Fayad 52

The presence of teeth assist retention, stability and support of the removable prosthesis.

Treatment Concepts:

1- Location of the defect. The distal portion of the maxilla are usually included in the surgical resection and the distal abutment is rarely remain. Therefore for most patients, a Kennedy class II partial denture with extensive lever arm is required.

2- Movement of the prosthesis: The defect must be used to minimize the movement of the prosthesis to reduce the stress on the abutment teeth.

3- Length of the lever arm. Considerably longer lever arms are encountered in patients with intraoral surgical defects.

4- Arch form: Square or ovoid arch forms provides more bearing surface perpendicular to occlusal stress resulting in more stabe prosthesis during function. Tapering arch form gives less palatal shelf area and therefore support is compromised.

5- Teeth: Preservation of the remaining teeth is important for retention and esthetics. The partial denture design must prevent the natural teeth from any pathologic stresses during functional. Maximum retention, stability and support should be obtained from the defect.

Aramany’s classification of maxillary defects:

Maxillary defects have been classified according to the defect location and its relation to the remaining teeth.

Class I: lateral defect with anterior margin approaching the midline.

Class II: Lateral defect with anterior margin away from the midline.

Class III: Middle defects surrounded by remaining dentition.

Class IV: Lateral defect with anterior margin crossing the midline.


Mostafa Fayad 53

Class V: Defect with anterior teeth remaining.

Class VI: Defect with posterior teeth remaining.

Partial denture design:

Diagnostic casts are surveyed carefully to locate the undercuts, the contour of guide planes, and selection of the path of insertion. Often a compound path of insertion must be employed to use the undercut in the defect. For example, if lateral and posterior undercuts will be used, the obturator is inserted into the defect first and then rotated into position onto the teeth.

The basic principals of partial denture design should be followed :

-Major connectors should be rigid,

- Occlusal rests should direct occlusal forces along the bony axis of the teeth,

- Guide planes should be designed to facilitate stability and bracing,

- Retention should be within the physiologic limits of the periodontal ligaments. The clasp arms should be passive when not functionally stressed and provide minimal retention needed to resist displacement.

- Maximum support should be gained from the residual soft tissues.

- Indirect retainer should be distributed as even as possible.

Aramany classes 1, II & IV ”

These defects are considered together because they share the same cantilever stress

patterns. A Kennedy class II partial denture with an extensive lever arm is required for these

patients.

Defferent partial denture designs were suggested to achieve adequate retention and to ensure proper orientation of the prosthesis. A rest and retainer should be placed on


Mostafa Fayad 54

the tooth closely adjacent to the anterior margin of the defect. If this concept is not employed, the prosthesis will tend to rotate out of retentive areas posteriorly.

Often the bony support for the tooth adjacent to the defect is compromised and does not permit its use as abutment. Other adjacent tooth should be used for this purpose. This compromised abutment can be treated endodontically with amputation of the crown and the root serves as an ”overdenture“ abutment.

Different suggested partial denture designs. Note fulcrum line in relation to defects.

Multiple occlusal rests may be used to improve stability and support. The fulcrum line is determined by the position of the occlusal, incisal or cingulum rests.

Sometimes lingual retentive clasp arms with buccal reciprocating arms are used depending on the angulation of the abutment teeth.

Since there is no cross-arch reciprocation of either buccal or lingual retention, this partial denture must be viewed as a unilateral partial denture and both buccal and lingual retentive arms may be considered to obtain cross-tooth retention and reciprocation.

Dentulous patients with partial maxillectomy defects ” Aramany class II“

In Aramany class II the prosthodontic consideration are similar to the total maxillectomy except that the prosthetic prognosis improves as the margin of the resection moves posteriorly.

If the maxillary cuspid of the defect side remains. The prosthetic prognosis improves dramatically. Even the presence of a central or lateral incisor on the defect side will enhance the stability and support of the prosthesis. The fulcrum line is dependent on the placement of occlusal rest. As more teeth are retained on the defect side, the fulcrum line shifts posteriorly. If bicuspid teeth remain the fulcrum line will be similar to a conventional Kennedy class II partial denture .


Mostafa Fayad 55

Indirect retainers should be placed as far anterior as possible from the fulcrum line. If adequate retention, stability, and support can be obtained from the residual dentition and soft tissues, no need to engage the defect aggressively.

The partial denture designs of Aramany Class II defect is similar to Kennedy Class II partial denture.

Class I design: The design can be either tripodal or linear.

Tripodal design: Two or three anterior teeth are splinted. Retention and bracing (labial and buccal retention and palatal bracing) and support are derived from the central incisor and the most posterior abutment tooth. Indirect retention is utilized by the location of a rest on the canine, or on the distal surface of the first premolar.

The linear design: If the anterior teeth are not included in the design, a linear design is recommended. Where the unilateral design requires bilateral retention and stabilization (diagonally placed on the posterior teeth).

Class I. Left; tripodal design. Right; linear design.

Class II design

The triangle formed by the fulcrum and lines through the anterior and posterior teeth with the canine as an apex serves as a reference. As this triangle flattens and diminishes in area, the stresses on the posterior teeth increase, leading to more difficult considerations of retention and stress


Mostafa Fayad 56

distribution. Based on this principle class IV is the most critical, followed by class I and finally class II is the least.

canine (apex, A), the distal abutment B and anterior abutment (C, or D, or E).

In Class II design, the teeth next to the defect are splinted. Retention is placed buccally on all abutment teeth, and indirect retention is located on the opposite side of the defect. Guiding planes are on the proximal surfaces of the second molar and the tooth next to the defect.

Class IV design:

Cross tooth reciprocating retention (lingual retention on the molars and buccal retention on the premolars) are used. Guiding planes are placed on proximal surface of the tooth next to the defect and the posterior terminal tooth. It is indicated to use only light wires in an acrylic resin base for class IV definitive obturation if the remaining dentition is not optimal.

linear design for metal frameworks for a Class IV maxillectomy is indicated. Retention and bracing are diagonally opposed

Prosthetic procedures:

The mouth preparation is completed as outlined and master impression is performed to construct the partial denture framework. The master cast is made and the framework is designed and fabricated. The frame work is adjusted to the abutment teeth in the patient s mouth using disclosing medium. The undercuts within the defect are


Mostafa Fayad 57

blocked out on the cast and relief is placed over the scar band and lateral wall of the defect . Acrylic resin is molded to the framework and the defect in preparation for the altered cast impression.

The extension of the prosthesis is adjusted using modeling plastics. The extension is relieved and holes are made along the finish line to escape excess material. Adhesive is applied and an elastic impression material is used to complete the altered cast impression. While the impression is tacking the patient is directed to make eccentric mandibular movements. After setting , the impression is removed and examined. The master cast is segmented , the framework and altered cast impression are seated on the tooth segment, and the impression is boxed and poured in dental stone. Conventional methods are followed to complete the prosthesis.

The obturator portion is made hollow and constructed from acrylic resin to allow for adjustment and rebasing. Slight pressure against the cheek is desirable to ensure maximum retention, stability and support.

Dentulous patients with partial maxillectomy defects which not involve thealveolar ridge and teeth .“Aramany class III”

This is essentially a tooth supported partial denture with central obturator extension. Conventional clasping elements are selected according to the position and condition of remaining dentition.

The partial denture design of Aramany Class III is essentially a tooth- supported partial denture with central obturator extention.

The Class III defect can be treated by tooth supported partial denture with central obturator extension.


Mostafa Fayad 58

Class III: retention, bracing and support are derived from four widely separated abutment teeth.

It is unreasonable to make any support from extension into the defect space, although soft liner extensions above the lateral palatal shelves may be useful. If the junction of the hard and soft palates is involved, construction of an obturator for this type of defect is more difficult than it appears, as the obturator must maintain contact posteriorly and laterally during soft palate elevation.

Thermoplastic is used to record the functional impressions of the tissue bordering the defect. Speech is usually normal after delivery of the prosthesis. However the patient will note excessive fluid leakage when swallowing . To alleviate this problem 5-10 mm extension is placed across the intact soft palate. During function the soft palate will lift from this extension, but this shield will serve to direct food and liquids into the oral pharynx. Extension into the defect with contact with the nasal side of the soft palate during elevation also is suggested.

Patients with bilateral total maxillectomy defects ”Aramany class V”

Class V design:

The design for Class V maxillary defect. Splinting of the anterior teeth is recommended. Tripodal design calls for buccal retention and palatal bracing. Support is derived from the splinted components, and indirect retention is located on the central incisors.

When both maxillae have been excised, the prosthetic prognosis is quite guarded. Prostheses constructed for these patients are primarily for speech and esthetics. However, without bony support the prosthesis will exhibit considerable movement during mastication and swallowing and placed tremendous stress on the remaining anterior


Mostafa Fayad 59

teeth. When retention is compromised, consideration must be given for creating undercuts surgically. Silicon or two-piece prosthesis may be used to increase retention. Splinting the anterior teeth and the use of gate or swing lock prosthesis will distribute stresses to anterior abutment teeth and may provide favorable situation for support in this case.

Swing lock prostheses may provide favorable situation for

support in class V defect patient.

If a large portion of the orbital floor is surgically removed, the incidence ofdiplopia is increased. In these cases prosthesis are often useful to support the orbital contents. The prosthesis may be fabricated as a one-pice in which the antral extension is attached directly to the obturator or in two section in which the superior orbital extension is connected to the obturator section via an attachment. The antral section may be flexible or rigid. The advantages of flexible apparatus are that, it is light in weight and it minimize the movement generated by the obturator during function.

patient with surgical resection of premaxilla “Aramany class VI “.

This defect will usually be smaller in area then the class V defect, so the gravitational movement will be less important and conventional clasping may be used to support this extension.. However, resection of this type can leave the upper lip totally unsupported or missing. The acrylic resin extension will be designed to position and hold the lip in an esthetic position . If the lip or nose is resected, the obturator may be designed to hold a facial prosthesis. If the remaining teeth can tolerate full coverage, a cross arch bar splint can dissipate rotational stress to the anterior abutments and also give additional retention to the prosthesis .

Partial denture design with conventional clasps for Class VI defect.


Mostafa Fayad 60

Double swing-lock partial denture with acrylic esthetic overlay engaging remaining teeth.

Defect is usually less stressful to remaining posterior teeth. Full palatal coverage and

conventional clasping are effective to retain and support the prosthesis.

Class VI defect, conventional clasping may be used to support this extension.

Technique of Construction of Definitive Obturator:

The same procedures of making the conventional partial denture are followed with attention is focused during impression to record the defective area.

4- Patient with total soft palate defect

Patient exhibiting considerable movement of the residual palatopharyngeal complex during function have excellent prosthetic prognosis for achieving normal speech.

Patient with little or no movement of the remaining palatopharyngeal mechanism makes it difficult to achieve normal speech with either surgical or prosthetic reconstruction. The obturator is attached to a conventional prosthesis. For dentulous patient, the obturator is constructed from acrylic resin and retained to the metal framework of the denture. The obturator should contact the remaining musculature of the


Mostafa Fayad 61

palatopharyngeal mechanism during function. The optimal level of the obturator in the nasopharynx is determined by the position of movement of the residual palatopharyngeal mechanism. Passavant’s pad and the anterior tubercle of the atlas bone can vary in location in relation to normal palatopharyngeal closure. Therefore, it is difficult to define a definite land marks for placement of the obturator.

As a general rule the following guide lines should be consider for location of the obturator for adults:

1- The obturator should be located in the nasopharynx at the level of normal palatal closure.

2- The inferior margin of the obturator should be placed at the level of greatest

muscular activity exhibited by the residual palatopharyngeal complex.

3- The inferior extension of the obturator will usually be an extension of the palatal plane as extended to the posterior pharyngeal wall.

Methods of construction:

The conventional prosthesis should be fabricated first. In obtaining impressions for diagnostic casts, the palatal portion of the tray should be extended with wax to record the defect. Partial denture designs should consider the long lever arm created by the extension for the obturator. Multiple occlusal rests on either sides of the fulcrum line will increase stability and resist the downward displacement of the obturator. Multiple retainers should be used with the retentive arms engaging distal undercuts.

If the patients has an anterior edentulous area, crown should be placed on the adjacent abutment teeth with the attachment of an anterior bar. The base will act as an indirect retainers and give excellent stability for the obturator extension .

If the defect is too large, acrylic tray is added to the retentive meshwork or wire loop to approximate the area of the defect. The acrylic tray is adjusted and checked with disclosing wax to ensure that contact does not occur with the lateral and posterior walls when the patient says ”ah“.

Warm modeling plastic is added to the tray and placed in the mouth. The modeling plastic should be as worm as the patient can tolerate because the pharyngeal tissues dontcontract forcefully except in swallowing. The patient is instructed to move his head in a circular manner from side to side, to extend his head as far forward and back as possible, and to speak and swallow. These movements activate the remaining palatopharyngeal


Mostafa Fayad 62

musculature and shape the modeling plastic. Since swallowing makes a more forceful closure, it should be performed at the end of the sequence to avoid underextension of the obturator. When the modeling process is completed, the patient is asked to speak, to swallow and to breath through the nostrile to test the effectiveness of the formed obturator. Then, all extensions are reduced 1 mm with a sharp scalpel, a mouth temprature thermoplastic wax is added to the obturator, flamed, tempered, and placed in the mouth for approximately 5 minutes. The previously described functions are repeated several times.

The prosthesis is removed, chilled with cold water and examined. Excesses wax are trimmed and additional wax are applied to the deficient areas. The wax is flamed and tempered, the prosthesis is reinserted, and functional movements are repeated. When the obturator appears adequate, the prosthesis is tempered in water bath and replaced in the mouth for 1 to 3 hours. The patient is instructed to wear the prosthesis without removal and to speak, swallow and perform the previously described movements. Before removal of the prosthesis, the patient is instructed to gargle with cold water to chill the wax.

The obturator is converted into acrylic resin in a customary manner. If the obturator is extensive hollowing is usually indicated. The oral surface of the obturator should be concave to provide adequate space for the tongue. The superior surface should be convex to deflect the nasal secretions into the oropharynx. The final contour of the obturator are determined with the prosthesis in the mouth using pressure-indicator paste.

Following obturation the movement of the palatopharyngeal complex may be increased and the obturator may require reduction after delivery.

Size and position of obturator:

The lateral dimensions are determined by lateral and posterior pharyngeal wall movement. As the position and length of the superior extension are controlled by the prosthodontist, too extensive superior extension should be avoided (approximately 10mm is adequate).


Mostafa Fayad 63

Methods to Improve Retention of Acquired Obturators

Securing retention of a prosthesis is a vital factor in its efficiency and in patient's

comfort. Acquired palatal defects usually present problem in prosthesis retention,

especially in edentulous patients. This can be overcomed by:

1- Engagement of the scar band formed at the skin-graft mucosal junction. As this area

contracts during healing it does so like a purse string creating a lateral undercut superior

to the scar band. Engagement of the scar band superiorly, and inferiorly improves

retention of the prosthesis.

2- Extension of the obturator against the lateral wall of the defect . In patients with

lateral maxillectomy defect, the axis of rotation is located along the medial margin of

the defect (class I,II,IV), the lateral portion of the prosthesis will exhibit the greatest

degree of movement.Extension of the prosthesis, and tissue contact superolaterally will

minimize vertical displacement of the prosthesis .

3- Resilient lining material; the use of resilient lining material may be indicated to

engage more undercuts in the defect. Definitive prosthesis with flexible obturator (soft

silicone material) will permit the engagement of bony undercuts more aggressively, thus

improving retention of the appliance .

4- Hollowing the obturator portion; large extensions of the prosthesis into the defect

should be made hollow to reduce the weight and vertical downward displacement of the

appliance.

5- Refitting the base; changes in the tissues supporting a maxillofacial prosthesis may be

rapid than those supporting a complete denture thus ,base adaptation must be re-evaluated

frequently and corrected by relining or rebasing to compensate for tissue changes .

6- Osseointegrted dental implants Recently, excellent retention and stability can be

provided by the placement of osseointegrated dental implants in residual alveolar ridges


Mostafa Fayad 64

and within bony regions of the defect. This improves the retention of the prosthesis

significantly.

The osseointegrated implants, placed into multiple regions of bone within the defect

provide a rigid, immobile base which can be used to retain the prosthesis using suitable

attachment system (magnets or clip bar attachment). The prognosis of osseointegrated

implants for irridated patients is less favorable because of changes in the supporting

structures .Successful osseointegration can be achieved by the use of hyperbaric oxygen

therapy, this improves hypoxia , hypocellularity and hypovascularity in irradiated

patients.

7- Two piece obturator, sectional obturator : It is used for edentulous patients with

acquired palatal defect involving large area of the palate. This usually presents a problem

in prosthesis retention. To ensure effective retention, the prosthesis must be extended

sufficiently to engage more undercut within the defect, with the result than that path of

insertion may present a great problem. Two piece obturator (sectional obturator) with

different paths of insertion will solve this problem, and increases retention. This also is

valuable for patients with bulky prosthesis and small mouth opening. The path of

insertion of the two pieces should be different to help in retention. The obturator portion

is constructed with two projections parallel to each other. The obturator portion is

inserted to engage undercuts in the defect, an overall impression is made, and the denture

base is constructed on a cast obtained from this impression. The two parts and related

together by attachment, hook or magnets.

8- Magnets: Magnetic retention is an effective method for retaining maxillofacial

prostheses. Most of the prostheses incorporating magnets are sectional prosthesis, in

which each section of the prosthesis contain a magnet. When the sections are properly

oriented, the magnets attract each other so retaining the sections.

9- Clasping: For partially edentoulous patients, the presence of teeth will enhance

retention of the prosthesis. Clasp placement should be broadly distributed throughout the


Mostafa Fayad 65

remaining dentition. Clasps should be placed on abutments teeth adjacent to and distal to

the defect. Auxiliary clasps can be used.

"cross tooth" retention and reciprocation should be considered for cases with

lateral defects. Lingual retention with buccal reciprocation clasp is indicated for the tooth

away from the defect. This clasp design will disengage from the tooth during occlusal

movement of the prosthesis, reducing the rotational stresses transmitted to the posterior

abutment.

Means of retention for acquired defects obturators

1-Clasps in dentulous patients.

2-Undecuts in the defective area, especially when soft liner is used.

3- Buccal flanges engaging undercuts in teeth and ridge.

4-Maximum coverage to the remaining tissues.

5-The use of implants with attachments in the unresected side .

6-The use of two parts obturator; the first in the defective side engaging undercuts and the second covering the palate.

7- The swing-lock partial dentures.

8-Bar attachment and clip.


Mostafa Fayad 66

Labial flange made from flexible acrylic engage undercut.

Implant placed in the unresected side.


Mostafa Fayad 67

Swing lock type prosthesis for class V defect patient.

Left; bar soldered to crowns on cast. Right, fitting surface of partial denture obturator (for anterior defect) with clips.

Mandibular defects

Mostafa Fayad 1

Rehabilitation of mandibular defects

Causes of Bony defects of the mandible

-Trauma.

- Tumor resection

-Inflammatory disease

-Radio necrosis

Disabilities of mandibulectomy patients

Deviation of the mandible toward the resected site.

Scarring on the remnant mandible.

Limited range of motion.

Occlusion discrepancy.

Problems associated with discontinuity of the mandible in swallowing, speech, respiration and control of saliva.

Disturbance of appearance.

Classification of mandibular defects:

a) Marginal Resection ( Continuity defects):

Superior resection of the alveolar bone leaving the inferior border intact.

1- Anterior marginal resection:

May include part of the tongue and floor of the mouth → if the arch isn't restored in a short time → remaining teeth will be no longer in the neutral zone and the buccal musculature will cause severe lingual tilt of remaining teeth → so, selective extraction and use of labial bar major connector design will improve the condition.

Mandibular defects

Mostafa Fayad 2

- After resection → an interim prosthesis must be fabricated and inserted during healing period to prevent collapse of mandibular segment.

- R.P.D. design will be typical to class IV design.

2- Lateral marginal resection:

- Definitive prosthesis is constructed after sufficient healing period has passed.

- The most important considerations:

a) Firm and non movable tissues.

b) With normal buccal and lingual vestibular depth is favourable.

- R.P.D. framework design will be typical to class II design.

b) Segmental Resection ( Discontinuity defects):

Complete resection of a segment of the mandible from the alveolar crest to the inferior border of the mandible.

- Resection often in the region of 2nd premolar and 1st molar.

- Resection should be through the alveolus of an extracted tooth rather than interdental bone to:

1- Preserve supporting bone distal to the last tooth.

2- Used as 1ry R.P.D. abutments.

- Increase the size of the resected mandible → increase degree of severity.

A] Treatment of mandibular defects

a) Surgical reconstruction using a bone graft

It is the best approach that a surgeon can take to correct defects of the mandible. The bone graft restores continuity to the mandible and provides a prosthesis-bearing area. However, surgical reconstruction may be contraindicated in patients receiving radiation therapy or in individuals with residual tumors.

Mandibular defects

Mostafa Fayad 3

Optimal treatment involves placement of endosseous implants in the bone graft, which help to anchor removable or fixed prostheses. The implants also minimize bone resorption and add to patient comfort.

In marginal mandibulectomy (the mandible remained continuous), the patient can be restored with an implant-supported prosthesis for the lower jaw.

Prostheses for segmental resection of partially Dentulous mandible

Snap-on prostheses can be designed and serve as a final removable partial denture can be designed in the form of snap-on prostheses. The selected abutment teeth are crowned, splinted and cemented in place. Bilateral bracing is important to minimize stress on any one tooth and to offset the lateral forces exerted by the slight jaw deviation which still persists.

A Dolder, Andrews, or Baker bar is splinted to crown and clip attachment is embedded in the denture base . the final partial denture with the clip snape onto the bar(fig 3).

Fig 3A, Baker bar splinted to crowns. B, the clip is embedded to the fitting surface of the denture base C, snap-on prosthesis in place.

Prostheses for segmental resection of fully Dentulous mandible

In such case the multiple abutments should be crowned and splinted before the final removable partial denture is constructed. This resection prostheses provides acceptable occlusion

Prostheses for anterior marginal excision of edentulous mandible.

The construction of prostheses for anterior marginal excision of the edentulous mandible require additional care. The huge intraoral vertical dimension must be restored, and a heavier denture is often constructed, sometimes unconventional prostheses with springs may be constructed to bring the teeth to acceptable occlusion and the lip to normal alignment.

Mandibular defects

Mostafa Fayad 4

Prostheses for partially resected edentulous mandible

The prostheses in such case are constructed manually for esthetics. The denture base usually need plumping to improve the facial appearance. This plumping is done by adding more wax during the try-in phase to open the patient's facial symmetry. These plumping should be passive to avoid unset of the denture by muscles impingiment. The acrylic teeth may need reshaping by grinding the buccal of the upper and the lingual of the lower to stabilize indirectly the denture during various mandibular excursions.

B] Treatment of mandibular deviation

The most serious sequel of acquired mandibular discontinuity is deviation. The mandible deviates towards the affected side.

The dentulous mandibular discontinuity patient is at a more advantage over their edentulous counterpart in the correction of deviation.

Frontal plane rotation. A, As the force of mandibular closure increases, the mandible rotates around occlusal contacts on the unresected side, and (B) the remaining teeth on the resected side drop further out of occlusion.

1-Immediate post surgical intertmaxillary fixation. Maintaining this fixation for several weeks and reapplying elastic for several hours daily to preserve the occlusal relationship.

2-Palatal acrylic resin ramp (deviation appliance); It is easiest and most practical device, it is consists of acrylic resin ramp on the palatal incline of the non-affected side. This is a functionally generated platform that slopes occlusally away from the maxillary dentition and engage the remaining mandibular teeth as closure begins.

Mandibular defects

Mostafa Fayad 5

- Acrylic Ramp Vs Metal Ramps: Acrylic ramps are advantageous because:

1) Periodic revisions and adjustments of the ramp are possible.

2) The final desired position doesn't have to be achieved with the 1st application of acrylic resin.

3.Physical manipulation: The most effective treatment is by early physical manipulation of the proximal fragment towards the unoperated side. This is done as soon as healing permits (within 2 weeks). It will be most effective in preventing scar contracture and breaking up tissue adhesion.

4-Training flange ( Guiding flange prosthesis): is used to train the masticatory muscles to close in normal occlusal relation. It is a flat cast or acrylic resin vertical extension from mandibular partial denture, or cap metal splint. It should be long enough vertically to engage the buccal surface of maxillary teeth on maximum function opening.

Patient with a lateral tongue mandibular discontinuity defect. The left lateral tongue was reconstructed with a myocutaneous flap. A, Mandibular prosthesis in position. B, Maxillary prosthesis in position.

Note the functionally generated occlusal platform or palatal ramp, (arrows). C and D, Note the angular path of closure.

The partial denture framework designs should positively engage most of the remaining dentition, to prevent movement of individual teeth. The training flange is usually designed to extend vertically from a continuous clasp along the buccal surfaces of the maxillary bicuspids and molars.

Mandibular defects

Mostafa Fayad 6

The flange may be constructed to extend from maxillary palatal plate and lies in the lower lingual sulcus in contact with the lower lingual surface of the lower molar and gingiva on the sound side.

This flange is constructed from Victoria metal, German silver or brass sheet 0.7 to 1 mm thick and recurred metal; cap splint at the opposite side of the defect.

When the patient open his mouth for enough the flange looses contact with the upper teeth and the mandible displace toward the resected side, with the result that the patient is unable to close again as the flange comes into contact with the palatal mucousa giving pain with the occlusal surface of the upper teeth. To close the mouth the patient should push the mandible towards the sound side by hand, or later the masticatory muscles can pull the flange to clear the upper teeth and help it to lie again in the upper buccal sulcus. This necessity of pulling the mandible into normal position every time the mouth is closed trains the muscles. At first a voluntary effort was needed by the patient's hand but in a short time it becomes involuntary ( by the muscles of masticartion).

Mandibular guidance prosthesis with jaws opened.

Acrylic mandibular guidance prosthesis with jaws closed.

Metallic mandibular guidance prosthesis with jaws closed.

Another design include a split splint with a buccal superior flange that attached to the lower teeth. In 3 weeks this " training splint" resulted in unilateral muscle development that compensated for the loss of bone in the other side, so that on opening and closing the mouth, the teeth met in normal occlusion.

After treatment if there is still slight mandibular deviation two rows of back teeth might be used on a the upper denture to get occlusion in two positions or imprints in the acrylic base palatal to t he upper posterior teeth are made to occlude with the lower posterior teeth.

Mandibular defects

Mostafa Fayad 7

5- Maxillary guidance ramp:

- Preferred for patients with severe mandibular deviation.

- Constructed of acrylic resin or cast or wrought wire retainers.

- It serves as interim prosthesis until acceptable occlusion is established.

- Technique:

1st Visit:

1) Full palatal coverage prosthesis is constructed following conventional prosthetic guidelines and then fitted and adjusted in the mouth.

2) Mandible is guided until proper occlusion → occlusal contact with palatal prosthesis is noted.

3) Prosthesis is removed and a mix of autopolymerized acrylic resin is prepared and added to the palatal prosthesis along lateral and anterior borders of non defect side.

4) The prosthesis replaced in the mouth and mandible is moved to desired position forming a palatal index → lingual to maxillary teeth.

5) The prosthesis is then removed to allow for completion of polymerization.

6) Smoothing, finishing and polishing → patient instructed to wear the prosthesis continually.

7) The index shouldn't extend below level of maxillary teeth, because:

a) Interfere with speech.

b) Interfere with deglutition.

c) Interfere with other oral functions requiring tongue manipulation.

2nd Visit:

1) The mandible will usually exhibit more movement laterally toward non surgical side.

2) Adjustment of palatal ramp is done to enable the mandible to assume proper maxillo-mandibular relationship.

3) When intercuspal position is achieved → Mandibular guidance prosthesis isrequired.

Mandibular defects

Mostafa Fayad 8

Success of mandibular guidance therapy varies and depends on:

1) Nature of surgical defect.

2) Early initiation of guidance therapy.

3) Patient cooperation.

4) Radiation therapy.

5) Amount of soft tissue dissection

Mandibular defects

Mostafa Fayad 9

C]- Lip and check support prosthesis.

In patients had mandibular resection and reconstruction; initially lip prosthesis can be constructed to support the patient’s lower lip and cheek to improve the external cosmetics. Final mandibular resection prosthesis with teeth and pink acrylic support the lower lip.

Intra-oral view of lower jaw surgery and reconstruction.

Lip support prosthesis. Final mandibular resection prosthesis with teeth.

The lips play an important role in the articulation of speech. An intact lower lip is

more important for speech than the upper lip because of its greater potential for

movement.

The prosthetic replacement for the lower lip and the retention of this prosthesis is

difficult because of movements of the mandible and the presence of saliva. Usually the

surgical reconstruction of the lower lip is the treatment of choice whereas prostheses for

replacement of a resected lower lip will aid speech and saliva control.

Facial paralysis may be resulted from trauma, infection, Cerebravascular accident,

or bell's palsy. Because the facial nerve supplies the motor and sensory innervation for

the buccinator and circum oral musculature, the loss of innervation of these muscles will

result in sagging of the affected side of the face. Drooping of the eyebrow, cheek, corner

of the mouth and lip lack of tonus and drooping of the corner of the mouth with

Mandibular defects

Mostafa Fayad 10

compromised saliva control are also associated with facial paralysis. On unilateral

paralysis, the muscles of the unaffected side of the face exert an abnormal pull on the

paralyzed side leading to chronic spasticity of the uninvolved muscles. The articulation

of speech may be affected with varying degrees.

To test the function of the facial nerve, instruct the patient to alternate between

"oo" and "ee" sounds normally semishencteric posture is assumed during the production

of the "oo" sound and a tense and spread posture for the "ee" sound.

Lip support prostheses may be beneficial to patients with facial nerve paralysis.

These prosthetic aids can be constructed with maxillary removable partial denture. Open

wire loop of 8-guage half-round wire is attached to the upper denture in the first premolar

area. The loop should be adjusted to protrude from the from the mouth to be used as hook

to elevate and support the upper lip and the corner of the mouth.

The partial denture framework is adjusted, and the loop is covered with baseplate

wax. The wax is adjusted to achieve the desired support for the corner of the mouth then

the wax is replaced by clear acrylic resin .

Although this loop is strengthened the lip line, it is unesthetic and does not

improve facial sag and still permitted drooling and may cause distortion of bilateral (P

and B) and labiodental (F and V) speech phonemes.

Another technique

A maxillary removable partial denture framework with a retentive meshwork in

the biscuspid areais constructed. Modeling plastic is added gradually to the meshwork to

elevate the vestibular fornix and cheek while speech and esthetic changes are evaluated

until the desired contours are achieved. The modeling plastic are substituted by

autopolymerized acrylic resin.

Mandibular defects

Mostafa Fayad 11

D] Laryngectomy aids

Most tumors of the larynx are squamous cell cercinoms. After surgical removal of

the larynx an alternative airway is required. A tracheostomy is performed creating notch

area of the neck to provide air exchange while bypassing the nasopharygeal airway.

Large number of patients with larygectomies may be required top wear a prosthesis to

prevent stenosis of the stone.

The use of metal tracheostomytube (silver alloy) may cause many problems, such

as tarnish, irritation, infection, difficulty in cleaning and to achieve proper angulation,

erasion of the trachea and formation of tracheasophageal fistulas.

A custom-made silicone rubber tracheostomy tube can be used to prevent stenosis

of the stoma with comfort and minimal complication. It is flexible, inert, adjustable and

can be molded to reproduce anatomic detail.

Technique of fabrication

Baseplate wax is adapted to the superior portion of the tube to serve as a tray for

makiking an impression of the tracheostoma and the surrounding structures. The tray

suction is used to clear the trachea of secretion. The tracheostomy tube should not be

obstructed to ensure an adequate airway during the impression procedures. The tray is

coated with adhesive and a fast- setting algenate is used to make an impression of the

anatomic contours of the depression and the stoned opening.

The impression is removed and poured with dental stone is stage to create a three-

piece mold. A copper tube of a guage similar to the material diameter of the standard

tracheostomy tube is incorporated into the mold to maintain an adequate airway in the

prosthesis the mold should be modified to incorporate a deflection in the finished

prosthesis to direct air and tracheobronchial secretions away from the patient's face.

Mandibular defects

Mostafa Fayad 12

Inert earth segments may be used to blend the silicone rubber to reproduce the

basic skin shade before the silicone is packed into the mold. Nylon mesh may be used to

add edge strength to the prosthesis. To facilitate retention of the prostheses, fabric tape

ties can be embedded within the silicone before closing the mold.

Duplicate prostheses should be made for each patient and it is advisable to save

the mold for feuture use. The patient is instructed to clean the prostheses with soaped

water, and to wear the prostheses constantly for 3 weeks or more to prevent stenosis.

When the stoma opening has stabilized the prostheses need only be worn at night.

E] Trachestomy obturator

When breathing is compromised by infection or trauma a patient airway is

provided by tracheostomy. After improvement of patient condition the tracheostomy tube

is removed and the opening heals primarily or is closed surgically.

Occasionally it is desirable to maintain the patency of the tracheal stoma. However

the speech will be affected unless the tracheostomy is obturated. Obturation is

occomplished by patient finger or by wearing a prosthesis.

Method of fabrication

A thin mix of alginate is used to tick the impression with spatual precautions for

protection of the airway. The impression is poured in stone and the mold is scrapedto

develop a retentive flange. The obturator may be made of acrylic resin or silicone rubber

and tented to blend with the patient's skin tones. The prosthesis may be retained by cloth

tape or tissue adhesive. The patient is instructed to clean the obturator with water and

soap and to wear it continuously.

Mandibular defects

Mostafa Fayad 13

F] Tongue prosthesis

The large oral cavity created by the loss of the tongue and some related structures,

as floor of mouth, teeth and alveolar ridges makes great difficulty in the control of saliva

and liquid fluids tend to pool in the altered floor of the mouth and to seep around the

epiglottis thus stimulating the cough reflex and/or leading to aspiration. If the tongue is

only removed, the use of tongue prosthesis with the compensatory movement of the

mandible and cheeks may permit some articulation.

Technique of construction

A maxillary stock tray is modified by adding a wax to make alginate impression of

the mandible and the floor of mouth. If the mandible is partally edentulous, the tongue

prosthesis is incorporated into a removable partial denture.

The retentive meshwork of the framework is extended into the floor of the mouth

to provide support for the resin tongue prosthesis.

The denture base should extend into the oral pharynx and overlay the epiglottis.

The prosthesis is contoured with wax and tried in the patient mouth to ensure freedom in

lateral and protrusive movements, and to check for adequate palatal contact during

speech and deglutition and the epiglottis are not imbedded in its activity. The denture

base should extend over the epiglottis and larynx to provide a protective cover for the

airway. The dorsal surface of the tongue prosthesis is contoured to allow food and fluide

to be directed into the oral pharynx by the action of the cheek muscles.

After processing the denture base should be reevaluated with pressure indicating

paste to eliminate interferences with the floor of the mouth during muscular activity.

Speech may be improved by attaching a flexible tongue of silicone rubber to Mandibular

prosthesis. The tongue prosthesis is held in place by making a snap-ring and undercut

design in the Mandibular denture base at the level of occlusal table.

Mandibular defects

Mostafa Fayad 14

The tip of the tongue is flexible and elevated 2-3 mm above the denture base. This

position permits a positive contact with the palate during the formation of linguoalveolar

sounds (this mandible should be slightly protrusive during formation of this speech

sound. During closure the rubber tip of the tongue prosthesis depression. Allowing

contact of the posterior teeth.

In edentulous patient with little alveolar ridge remaining it is better to suspend a

tongue prosthesis for maxillary complete denture. Mouth sagerature wax is added to the

palate of a maxillary denture and modified.

Intraorally until maximum contact is developed with the floor of the mouth during

swallowing. Then the wax pattern is processed into acrylic resin. This prosthesis assist

swallowing but speech and salivary control are rarely improved .

Mandibular defects

Mostafa Fayad 15

Speech aid appliances:

- Factors that predispose to misarticulation of speech sounds:

1) Following mandibular resection → oral cavity decrease in size and portion of the tongue is excised or used for wound closure.

2) The sensory and motor innervations of the tongue may be compromised.

3) The sensory and motor innervations of the lips and cheeks are compromised by 1ry mandibular resection and radial neck dissection.

4) Varying amounts of mandible and number of teeth are removed.

5) Mandibular movements are altered.

6) Radiation therapy → Xerostomia.

Types of speech aid appliances:

I – Palatal speech aid:

- Constant sounds as "g & k" required valving by posterior surface of the tongue

with posterior part of hard palate and anterior surface of soft palate → very

difficult for mandiblectomy patient.

- If the palatal vault was lowered prosthetically into the space to accommodate for

restricted tongue movements → speech improvements might be noted.

- Restriction of tongue movement is divided to:

a) Extreme restriction: inability to contact either palate or maxillary

teeth with tongue.

b) Moderate restriction: partial tongue contact with palate or maxillary

teeth during speech.

Mandibular defects

Mostafa Fayad 16

- The palate is lowered by means of retainer for dentulous patient and palatal acrylic

resin extension onto the upper complete denture for edentulous patient.

- Functional impression of the dorsal surface of the tongue is done with hollow

palatal speech prosthesis.

- After 2 weeks a test should be done with 10 words contains "k & g".

II – Tongue prosthesis:

- Articulation is compromised in patients requiring total glossectomy.

- Silicone rubber tongue prosthesis placed following surgery → improving quality

of speech and help deglutition.

Maxillofacial Splints

Mostafa Fayad 1


Jaw fracture

A fracture is the breaking of a bone or a bend in a bone and always has associated damage

to the soft tissue around the broken bone. Falls, sporting accidents and motor vehicle accidents

account for the majority of broken bones. There are 206 different bones in the body that hold us

up and produce blood and blood cells essential for life.

A fractured lower jaw may be life threatening as it may cause an obstructed airway

particularly if the patient becomes unconscious. The treatment of jaw fracture requires reduction

of the fractured segments in the proper position, immobilization till bony union occurs and

rehabilitation to restore normal functions.

Types of fractures

Closed-Simple The bone is fractured but the skin is still intact

Open- Compound The bone is fractured and protrudes through the skin.

Complicated This is a major fracture involving damage to vital organs or many

blood vessels damaged

A greenstick fracture is one in which the bone is not broken completely through.

Because the bones of young children are relatively soft and pliable, it is in this age

group that such fractures are generally encountered.

Comminuted fractures: These are fractures that exhibit multiple fragmentation of

the bone at one fracture site.

Telescoped or impacted fracture: This type of injury is rarely seen in the

mandible, but it implies that one bony fragment is forcibly driven into the other.

Pathologic fracture: A pathologic fracture is said to occur when a fracture results

from normal function or minimal trauma in a bone weakened by pathology.


Mostafa Fayad 2

A blow to the chin can cause a fracture at the parasymphyseal region (so-called "direct

fracture") and the fracturing force may be transmitted to the opposite condylar area, causing a

subcondylar fracture (so-called "indirect fracture").

mandibular fractures are frequently influenced by muscular displacing forces. Whether or

not the fragments become displaced by the muscular forces depends on the direction of the

fracture plane. When it is parallel to the muscular pull, the fracture plane allows displacement of

the fragments (unfavorable fracture). When the fracture plane is in the opposite direction, the

muscle pull is advantageous (favorable fracture)

Common Sites of mandibular Fracture

_ Condyle 36% _ Body 21%

_ Angle 20% _ Parasymphysis 14%

_ Coronoid, ramus, alveolus, symphysis 3%

_ Weak areas include 3rd molar and canine fossa


Mostafa Fayad 3

• for the middle facial third, the most common is a fracture of the zygomatico-maxillary

complex (53%)

• luxation or subluxation affects mostly the teeth of the upper jaw (72%)

• soft tissues of the chin and cheeks get injured most often, followed by tissues of the upper

lip and nose.

Radiological examination

At least two views are usually needed to demonstrate a fracture adequately.

Teeth. Periapical view is supplemented by another intra-oral view from an oblique angle, e.g.

oblique occlusal or bisecting-angle periapical.

Dento-alveolar fracture. Periapical(s) and oblique occlusal views.

Mandible. Panoramic film and postero-anterior (PA) of mandible are the basic views. A reverse

Towne's (modified PA) is useful for suspected condylar fractures. True occlusal views of a

fracture in the body or symphysis are helpful.

Zygoma (or malar) fractures. Occipitomental (OM) and OM30° views are required.

Maxillary fractures. OM, OM30 views of true lateral facial bones and computed tomographic

scans are helpful for complicated fractures.

Nasal fractures. True lateral nasal bones, sometimes with the addition of superoinferior nasal

bones: both are taken using occlusal films.

Nasoethmoidal fractures. Views are as for maxillary fractures.

If more accurate information of the involvement of the temporomandibular joint is required, axial

and coronal computed tomography (CT) scans offer an excellent opportunity to study the fracture

details.


Mostafa Fayad 4

Goals of Therapy

1. Obtain stable occlusion.

2. Restore interincisal opening and mandibular excursive movements.

3. Establish a full range of mandibular excursive movements.

4. Minimize deviation of the mandible.

5. Produce a pain-free articular apparatus at rest and during function.

6. Avoid internal derangement of the temporomandibular joint on the injured or the

contralateral side.

7. Avoid the long-term complication of growth disturbance.

Treatment of jaw fracture:

Reduction: placing the fragments in their normal anatomical relation.

Immobilization: fixing the fragments in position by various means until healing and union is

completed.

Rehabilitation: restoration of normal function after complete healing.

Methods of immobilization:

Wiring: indicated when all or most of the natural teeth are present.

Arch bar: indicated when there is no enough number of natural teeth to enable effective

wiring.

Splints

Rigid osteosynthesis is the most modem development in maxillofacial trauma surgery.

Titanium plates and screws have superseded the stainless steel variants, and many patterns and

sizes are now available.


Mostafa Fayad 5

Wiring

1. Direct wiring: It is the method of choice in the earlier stages of treatment. Where an opposing two natural teeth are wired to reduce the fracture displacement by bringing the jaws into occlusion.

2. Eyelet wiring: Used when the patient has a complete or almost sufficient pairs or set of opposing teeth.

3. Inter-dental wiring: Used in single jaw fixation. In this method a single wire is passed around two or more teeth on each side of the fractured segments and tightened together. This method brings the fractured fragments into good position

4. Inter-osseous wiring: Used for fractured edentulous body of the mandible with displacement or fixation of un controllable edentulous post fragment.

5. Trans-osseous wiring: This is especially useful in the treatment of edentulous mandibular fractures or for control of the edentulous posterior fragment. It can be carried out at the lower border of the mandible through an extra-oral surgical approach or at the upper border from intra-oral incision.

6. Circumferential wiring.

7. External pin fixation.

Arch bar: Used when the patient has an insufficient number of suitably shaped teeth to enable

effective inter-dental eyelet wiring to be carried out.

Hammond Splint double arch bar:

It is used when displacement of the fractured segments

exists.

It is adapted to the neck of the teeth on both buccal and

lingual surface and fixed to them by wiring. Arch bar applications.

Impressions of the dental arches are made to obtain models onto which the bars are adapted.

The wire is then transferred and fitted to the teeth in the patient's mouth, and fixed in place

using stainless steel wire.


Mostafa Fayad 6

SplintsDefinition: a rigid or flexible device that maintains in position a displaced or movable part; also

used to keep in place and protect an injured part. GPT

it is an appliance used for immobilization of displaced or movable parts of jaw into their

original position after jaw fracture or re-constructive surgery until repair occurs.

Uses:

In the treatment of fractured jaws: immobilize fractured segment till healing occurs.

In surgical orthodontics of malposed jaws: ex: mandibular prognathism after segmental

osteotomy to splint bone segments together.

In conjunction with bone graft.

In treatment of periodontally mobile teeth (periodontal splint).

To support resected mandible in its new position.

In holding another appliance e.g. training flange.

Advantages:

Provide good fixation of fractured segments for long period of time.

Allow early movement of the mandible so decrease trismus.

Not harmful to teeth and supporting structures as intermaxillary fixation.

Withstand strong inter-maxillary traction without extruding the teeth.

The problem of fragment rotation due to muscle pull and inter-maxillary elastics is eliminated.

Require little post operative attention.

May extend to restore edentulous fragment.

Serve as an excellent medium for applying traction to displaced bones. Especially the maxilla.

Disadvantages:

Some types of splints require accurate impression techniques and a skilled technician, which

becomes costly and time consuming.

Splints that cover the lingual or palatal surfaces tend to accumulate debris.

Metal splints require good standing teeth.


Mostafa Fayad 7

Requirements

Should be rigid and not allow mobility of the fractured segment.

Simple in construction with the least amount of pain or discomfort to the patient.

Made from radiolucent material to show fracture line in the x-ray.

Not affect function or interfere with occlusion with opposing teeth.

Comfortable to the patient and decrease patient injury.

Minimum injury to the standing teeth, bone or soft tissues.

Minimum disturbance to normal function.

Ease of construction.

Low in cost.

Impression of fractured jaw

Adequate light and suction should be present.

Use:

hydrogen peroxide to dissolve blood and remove food debris.

Sodium bicarbonate to dissolve mucous and control excessive salivation.

Flavored mouth wash.

Control trismus and pain by local anesthesia.

According to the presence or absence of displacement:

If there is no displacement of the jaws at line of fracture: make alginate impression and

poured to produce casts which mounted on simple hinge articulator.

If displacement occurs: use sectional impression to the fractured jaw with shallow stock

tray is made and another impression to the opposing jaw is taken and the impressions are

poured, the cast with fractured jaw is segmented with a saw at line of displacement and the

2 segments are reassembled into their original position guided by the occlusion of the

opposing arch and the 2 segments attached with plaster base on the articulator.


Mostafa Fayad 8

Types of splints

a) For dentulous patient:

1) Metal cap splint

2) Labio-lingual splint

3) Fenestrated splint

4) Occlusal waver splint

5) Palatal occlusal splint

6) Bite plane occlusal splint

7) Mandibular Lingual splint

8) Cast labial splint:

9) Guide flange prosthesis

10)Arch bar

11)Wire splints

b) For edentulous patient:

Gunning splint

c) For both dentulous and edentulous patient:

Kingsley splint

1. Cast metal cap splint:

It is a cast metal that covers the buccal, lingual and occlusal aspect of teeth on either side of

the fracture and cemented to the teeth. It provides a rigid and efficient form of reduction and

immobilization.

Indications:

Permanent teeth with fully erupted crown and definite undercuts

Delayed fracture if displacement occurs and fibrous tissue formed at fracture line which need

excessive reduction force that cannot be applied by acrylic splints


Mostafa Fayad 9

Long term immobilization in case of jaw resection and need of resection guiding flange

In TMJ exercise: by extra oral rode extend from upper and lower metal cap splint and elastic

bands in between the rods

In immobilization of bone segment in segmental osteotomy (ex: mandibular prognathism)

Types:

1. One piece cap splint (simple cap splint):

It is used when there is little displacement and position of the fractured segments can be

determined by the occlusion of opposing teeth without displacement of the jaws.

2. Two piece cap splint (cap splint with screw connecting bar):

It is used when displacement occurs and fibrous tissue present between the fractured

segments as it needs high reduction force. The two parts of the splint are connected together

by localizing plates and screws

3- The Modified Cap Splint:

This type is exactly the same as the normal cast metal cap splint except that the occlusal

surfaces of the teeth are left free.

Advantages of cap splints:

1-Provides effective fixation of jaw fracture even in the presence of few teeth in each

segment.

2-Rigid without being bulky, smooth and easy to clean.

Disadvantages of cap splints:

1-It interfere with occlusion as the occlusal surface is covered.

2-Expensive and time-consuming procedure.

Construction:

Impression of both arches with alginate is made with short tray flange as occlusal surface of the

teeth is only needed.

If displacement occurs, cast sectioned at line of fracture, casts are hand articulated, reassembled

and mounted on simple hinge articulator guided by the occlusion of opposing teeth.

Cast is surveyed, path of insertion is selected, undercuts were blocked out.


Mostafa Fayad 10

Sheet of wax is warmed and adapted on the occlusal surface of the teeth on the cast and the

articulator is closed to carry the imprints of opposing teeth. Wax should be thin and not

interfere with free way space and the periphery of the wax should be square (not knife edge).

Cusps of teeth may perforate the wax and project through the splint to decrease jaw separation

and help in escapement of the cement through the vents.

Tags (underplates) are embedded in the wax pattern which hold wire loop (overplates), it also

help in intermaxillary fixation.

a) Tags (underplates): it is the female element, waxed in the wax pattern or soldered later.

b) Wire loops (overplates): screwed to the tags with screw.

Wax pattern is invested and casted with direct or indirect casting system:

Direct system of casting: done directly over the cast, stone cast under cuts were blocked

out on the surveyor, then the cast is duplicated into refractory cast on which the wax

pattern is made

Indirect system of casting: wax pattern is removed from the cast (to verify that undercut

is blocked to avoid interference during insertion), invested and casted.

Cement the splints on the corresponding teeth, apply careful directed traction force to the bone

segments till assume proper reduction.

Wire loops screwed to the tags, use quick setting plaster to hold the position of the wire loop

in reduced state of fracture, after plaster setting wire loops unscrewed and removed while it is

attached to the plaster and the jaws are allowed to return temporarily to the displaced position.

Wire loops invested in the laboratory and connected together by soldering metal bar to them.

Reduce the fractured part again, the wire loops with connecting bar screwed to the tags.

Other method used to connect the 2 pieces metal cap splint using metal rode and metal tube:

the anterior portion contain metal rode (male part) and posterior portion have metal tube

(female part) that contain channel for rode and inserted before anterior portion, after reduction

the metal rode inserted into metal tube to immobilize fractured segments.


Mostafa Fayad 11

2. Labiolingual splint (sectioned-hinged, stout sectional splint,divided plastic splint) :

It is an acrylic band fits around the bucco-labial surfaces of the teeth as well as the

lingual aspects, leaving the occlusal surfaces uncovered. It consists of three sections; a

lingual section fits around the lingual surface of the teeth

and two labial sections around the facial surface of the teeth.

A stainless steel wire connects the two acrylic

portions posteriorly around the last remaining tooth. This

wire acts as a hinge.

A button divided into two halves in the midline is

used to secure the two labial sections by wiring.

Indications:

- Dentulous or partially edentulous patient.

- mixed dentition (children).

Construction:

Primary alginate impression is taken and poured to produce casts, if displacement of fracture

segment occurs, cast sectioned at line of fracture, casts are hand articulated, reassembled and

mounted on simple hinge articulator guided by the occlusion of opposing teeth.

A half round wire 0.9 mm is well adapted to the surface of the last standing tooth. The two

ends of the wire are bent to follow the contour of the buccal and lingual of the last tooth and

the tooth anterior to it. The wire is then bent at right angle to its length. This portion will help

to hold the wire in the flask.

Wax adapted on the labial, buccal and lingual surfaces and not cover occlusal surface of the

teeth (extend to survey line), wire embedded distal to the last molar tooth on each side to hold

buccal and lingual flange together, the wire form a hinge that allow open and close of splint

without fracture, wire hooks attached to the buccal surface of the appliance, blunt button

which have undercuts is made at midline.

A square wax button, 5 mm, is adapted in the midline of the facial surface. The model is

trimmed occlusally to the upper edge of the wax.


Mostafa Fayad 12

Wax is processed into clear acrylic resin, the acrylic button is divided vertically at midline

with a fissure bur or with a saw.

The splint opened and placed on the teeth, reduce the fracture and immobilization made by

tighten wire ligature around the 2 halves of the acrylic button, and buccally placed wire hooks

are used for intermaxillary fixation and attachment to the facial bone.

Labiolingual splint is classified according to the material from which it is constructed into :

i. Acrylic labiolingual splint ii. Cast metal Labiolingual splint.

The cast metal splint is used when a long-term immobilization strength and rigidity are

required. Cast metal splint offers superior fit, rigidity without being bulky. It is also smooth,

easier to clean and more comfortable for the patient. The reassembled casts are duplicated into

investment cast , the splint is waxed up on the duplicate cast, and casting procedures are then

carried out.

Advantages:

Not need intermaxillary fixation.

Not interfere with opposing occlusion.

Clear resin allow observation of tissue under the splint.

Easily constructed, easily adjusted and easily repaired.

Provide good oral hygiene (removable).

Retention from proximal embrassres and not need fully erupted

crown.

Radiolucent: allow monitoring of fracture union by x-ray.

Removed easily to test union of the 2 fractured part.

Can incorporate undercut in soft and hard tissues.

It fixes the fracture firmly and is retained by the teeth

interproximaally without cement.

Disadvantages:

Easily fractured as it not resist force of muscles in case of displacement of fractured segments

leading to misalignment of fractured segments.


Mostafa Fayad 13

3. Fenestrated splint:

It is a modified labiolingual splint (one-piece acrylic device or silicone). These splints are

used for short permanent clinical crowns, for deciduous teeth when no undercuts are available

for retention, and for badly decayed teeth. It is designed to fit a dentulous maxilla and mandible

through fenestrations created for the occlusal surfaces of the teeth

Indications:

Deciduous teeth with no clinical crown – badly decayed teeth – post radiation carries.

Construction:

Resemble labiolingual splint without button.

retention mechanically by friction into interproximal spaces.

fit the dentition of one arch through the fenestration of the

occlusal surfaces, wire tags or holes may be incorporated to

the buccal flange to facilitate immobilization.

4. Occlusal waver splint:

Indications:

This splint is used for intermaxillary fixation of fully dentulous

patients who have occlusion that is inadequate for a positive

index. (ex: unilateral open bite).

The occlusal and incisal surfaces of both arches are covered

with the splint. The immobilization is achieved with elstic bands on Ivy loops or arch bars This

splint is constructed of acrylic resin.

Construction:

May be made from acrylic or metal, occlusal surfaces of both arches covered with the

splint and immobilization done with elastic bands and arch bar. When thickness and strength

are critical, cast metal may be used.


Mostafa Fayad 14

5. Palatal occlusal splint:

It is useful for fixation of maxillary segmental fracture. It covers the palate, the occlusal

surfaces & the incisal edges including the incisal third of the labial surfaces. It is fixed to

the maxilla with inter-dental wiring.

Indications:

Fixation of maxillary segmental osteotomy – fracture of maxilla.

Construction

Covers the palate, occlusal surface and incisal third of labial surface of anterior teeth.

Fixation to maxilla by inter-dental wiring and intermaxillary fixation is not necessary.

Palatal Splint of Acrylic or Metal:

These clear acrylic splints can be constructed without covering the occlusal surfaces or the

incisal edges. The cast palatal splint is usually used in the treatment of a comminuted fracture of

the maxilla with collapsed arch.

6. Bite plane occlusal splint:

Indication

Bruxism – trauma from occlusion – tooth wear – clicking – pain – tenderness – premature

occlusal contact – disc displacement.

Construction

If vertical dimension lost, squash bite wax is used to restore VD at correct centric relation or

centric occlusion, then processed into acrylic resin and retained by Adams wire clasp or wired

to the interproximal embrasures of the teeth.


Mostafa Fayad 15

7. Mandibular Lingual splint:

This type of dental splint is conforming to the inner aspect of the dental arch. It is

considered as the most common surgical splint used today.

Used in para-symphyseal fracture of the mandible at midline to prevent collapse of

fractured segment lingually.

It is fixed with wire to the teeth or to buccaly placed arch bar(holes drilled for wire in the

acrylic at lingual embrasures).

Allow early movement of the mandible and prevent TMJ ankylosis as it not need

intermaxillary fixation.

The symphysis region is more difficult to reconstruct than the mandibular body due to the

abrupt curvature of the bone in this area.

8. Cast labial splint:

These splints are designed to withstand heavy traction forces as in cases in which

powerful forward traction is necessary. It is used in case of old, fused fracture of the

maxilla with displacement in which re-fracture and forward positioning are necessary.

9. Guide flange prosthesis

This is a training type of prosthesis. When the mandible is resected, a similar

situation occurs if continuity is lost at the midline. Lateral guide flange prostheses

are often used to control deviation of the residual mandibular segment after resection,

and as a re-training process of the neuromuscular system. Multiple retentive clasps in

widely distributed areas of the arch would be the best approach. Splinting of

weakened teeth should be seriously considered.


Mostafa Fayad 16

10. Arch bar:

Used for single jaw fixation.

There are various methods of attachment of the elastic bands: archbars, buttons or hooks,

fixed to the dentition under local or general anaesthesia, silver cap splints or simply

orthodontic brackets bonded to the teeth have all been used.

11. Wire splints:

a. Direct wiring: wiring of upper and lower teeth together.

b. Interden al wiring: wiring the adjacent teeth together

across the line of fracture.

c. Eyelet wiring: wire eyelet is made interproximally at the

line of fracture, each free wire end rotate around tooth,

enters the eyelet and tied.

d. Intra-osseous wiring: perforations around fracture line is made and the wire used through

it for reduction.

12. Vacuum-formed splints.

The management of fractures with occlusal disruption but without loss of vertical height is

simple, using elastic intermaxillary fixation attached

to Vacuum-formed splints 1 mm thick with bonded

wire cleats. Orthodontic elastics guide the patient into

centric occlusion

Advantages over other methods of fixation

include the fact that clinical work is completed

entirely at the chairside without the need for general

anaesthesia, the patient’s discomfort is minimal, laboratory time is reduced, the materials are

cheap and the magnitude and direction of intermaxillary fixation can be modified easily.

This method of treatment should be particularly useful in the management of mandibular

condylar neck fractures in children.


Mostafa Fayad 17

13. Gunning splint: (for edentulous patient)

It is made as a one piece for the two arches or two separate pieces (fig. 4-8). The two

pieces is easier to manipulate and to be wired to the jawbones. The splint can be made in

conjunction with elastic chin bandage to reduce pain and discomfort

Indications:

It is used for the fixation of mandibular or maxillary fractures in completely edentulous

patients. It is indicated when there is little displacement and there is no infection.

Types:

A. One piece gunning splint:

Upper and lower impression is made, if fractured segment displaced the cast is

sectioned on the fracture line and reassembled by plaster base.

Two shellac record bases and two wax rims are made on the casts.

Casts with record blocks are mounted on the articulator at proper vertical dimension

and horizontal relation.

Space created in the wax rim anteriorly from canine to canine for breathing, feeding

and to decrease postoperative vomiting.

Wax rims are sealed together and processed as one unit into acrylic resin.

After reduction of the fractured segments, the splint is immobilized extraorally with

elastic chin bandage (Barton bandage).

B. Two pieces gunning splint:

Allow early mobility of the mandible after removal of intermaxillary fixation as

separate maxillary and mandibular stents are made:

Two shellac record bases and two wax rims are made on the casts.

Casts with record blocks are mounted on the articulator at proper vertical dimension

and horizontal relation.


Mostafa Fayad 18

Space in the wax wade anteriorly at mid line, wire hooks embedded in the buccal

flange and used for intermaxillary fixation.

Holes in the buccal flange are made for wiring the upper splint to the facial bones,

root of zygoma, infra-orbital bone, lateral orbital rim, nasal spine, malar bone and

for circumferential wiring of the lower splint in the area of first molar.

Male projections (buttons) about 3mm are made on the occlusal surface of one wax

rim for anchorage by self cure to the grooves (female) on the other wax rim during

fixation (used as an index to maintain centric position).

C. Modified gunning splint:

It is made by modifying existing complete denture as

follows: repair the fractured denture, remove upper and

lower incisors, and fix upper and lower denture together

by asking the patient to bite on a piece of compound

which may be left or processed into acrylic resin to

obtain one piece gunning splint.

Faulty occlusion and reduced vertical dimension is corrected by adding colored

self-curing resin to the occlusal surface of the denture.

Hooks or arch bars are fixed to the facial surface for intertmaxillary fixation.

Holes are drilled on the upper denture flange for wiring the upper denture to the

facial bone to obtain two pieces gunning splint.

If existing denture lost fitness or develop occlusal discrepancies, use soft liner or

tissue conditioner, it also act as a cushion between hard acrylic resin and traumatized

tissues.


Mostafa Fayad 19

D.Gunning splint with training flange:

It is a 2 piece gunning splint.

Prevent deviation of the mandible to defect side after mandibular resection or

after irradiation due to fibrous tissue formation.

metal plate extend from the upper splint to the lingual surface pf the lower

splint, so the patient can't close except in correct relation.

at first, patient may use hand to guide the mandible to correct position then it

becomes involuntary by training of muscles.

E. Sectional Gunning splint

This splint is designed for immediate immobilization of the resected mandible to minimize

postsurgical deviation. It is the same as two-piece Gunning splint with indices designed for

possible use as a flange prosthesis and a locking mechanism for immobilization

14. kingsley splint: (for both edentulous and non edentulous patients)

Indication

Fixation of fractured maxilla both in dentulous and edentulous patient.

It is indicated for fracture of edentulous mandible as an alternate to gunning splint.

As an emergency treatment for depressed maxillary fracture where traction is required.

Construction

Acrylic or cast metal base plate which covers the ridge, palate and the teeth is made.

Metal rod is extended from the anterior part of the base plate, emerged through oral

commissar bilaterally and attached to vertical rod by universal joint.

Extra-oral immobilization of fractured maxilla is made by elastic or plaster head gear.

Modified kingsley splint:

o Used in emergency to prevent fall of maxilla on the dorsum of the tongue to avoid

suffocation.


Mostafa Fayad 20

o The upper tray filled with compound and attached to maxilla, metal rods soldered to the

tray are protruded from the lip to join to the vertical rode by universal joint.

o The vertical rode terminate in flat plate embedded in plaster head gear.

o An intraoral tray may be fitted to the teeth or edentulous ridge by compound impression

material. The tray has stout wires attacked and projecting between the lips around the

sides of the face. The wires provide attachment for bandage over the head in case of

maxillary fracture and below the chin in mandibular fracture.

Stents

Mostafa Fayad 1

Maxillofacial Stents

Stents are removable appliances constructed to cover the tissues and/or the teeth

for their protection, to carry medicaments, radium material or to control bleeding. They

were named after the dentist who first described their use Charles R. Stent.

Function:

Control bleeding.

Protect the tissue from radiation, maintain tissue in position, carry radium in the treatment of malignancy.

Carry medications.

Promote healing and decrease wound infection.

Protect teeth.

Protect skin graft and preserve the depth of vestibule after vestibuloplasty.

Materials:

1. Hard acrylic materials: heat cure, self cure acrylic resin, may be lined with soft liner or tissue conditioner.

2. Soft materials: Soft rubber or soft resins are used for special purposes. It can also

be fabricated from silicone vinyl rubber - poly vinyl vaccuform. but an additional

reinforcement of resin is usually required.

3. Modeling plastic, black gutta percha and silicone: In emergency cases where there

is no time to construct a stent, these materials may be used directly in the oral

cavity on the bleeding area.

Stents

Mostafa Fayad 2

Types:

A. Intra-oral stents:

1. Anti-hemorrhagic stent.

2. Medication carrier.

3. Fluoride carrier.

4. Radiation stents (prosthesis for radiotherapy):

a. Radium applicator (carrier).

b. Positioning peri-oral cone (Docking device).

c. Displacement (positional) stent.

d. Intra oral radiation protective stent ( tongue protector).

e. Positioning dosemetric device stent.

f. Stent for recontouring tissue to simplify dosemetery.

g. Positioning radioactive source.

h. Positioning radioactive source after loading.

i. Stent used in direct implantation.

j. Stent used to prevent tongue and check biting.

5. Pedodontic stent.

6. Periodontic stent (labio-lingual stent-cosmetic stent).

7. Paraplegic stent.

8. Drainage stent.

9. Cyst plug.

10. Occlusal stent.

11. Mouth guard.

12. Oral screen.

13. Trismus stents:

a. T.M.J exerciser (dynamic bite opener).

b. Inflatable bite opener.

c. Intra oral prosthesis with inter arch spring.

14. Stent for vestibuloplasty.

15. Palatal stent.

16. Stent for epulis fissuratum.

17. Stent for resected maxilla.

18. Stent for lip and check support.

19. Stents for implants:

a. Stent for surgical implant placement.

b. Stent for implant imaging.

20. Speech rehabilitation aid.

B. Extra-oral stents:

1. Extra oral radiation protective stent.

2. Stent for neck scar (burn stent).

3. Stent for nasal defect ( temporary nasal prosthesis).

4. Nasal stent.

5. Auditory stent.

6. Oro-facial plug.

Stents

Mostafa Fayad 3

A. Intra-oral stents

1. Anti-haemorrhagic stent:

Indication:

It is used in patients with tendency to severe bleeding following extractionor hemophilic patients to arrest bleeding.

It may be constructed in the form of a partial plate (acrylic) to control bleeding by applying gentle pressure to the extraction wound.

Such stents can be constructed in clear methacrylate with suitable relief to accommodate the hemostatic agent.

Construction:

Upper and lower impressions are made and the casts are poured and mounted on a simple articulator. The tooth to be extracted is removed from the stone cast.

A layer of molding wax is adapted on the cast to cover the buccal and lingual surfaces and the top of the ridge. The articulator is then closed to allow the opposing teeth to touch the top of the wax. The wax is processed in clear heat or chemical cure resin lining with soft resin, is advised.

The stent is inserted immediately after extraction. Bleeding is controlled as the patient closes and applies gentle pressure over the extraction site.

In patients with clotting problems as in hemophilia a stent could be of great help in the arrest of bleeding. But here no pressure should be applied. They are designed only to protect the socket and blood clot from the tongue and to hold a haemostatic dressing in place. It can be left in the mouth for a week or even more if needed.

The use of such stents is not considered essential in the management of hemophilic patients by many other oral surgeons, as it is believed that it may act as a source of irritation and possible infection.

So EL-ASSAL incorporates different ratios (5%) of well proved anti-inflammatory agent (Ketoprofen) in the Acrylic resin to decrease postoperative irritation or inflammatory reaction.[ JKAU: Eng. Sci., vol. 15 no. 2, pp. 33-43 (2004 A.D./1425 A.H.)]

Stents

Mostafa Fayad 4

2. Medication carrier:

Indication:

It is used carry medical paste (palliative paste) to contact oral mucosa as in case of chemotherapy and osteoradionecrosis.

Construction:

Acrylic base plate made on the diagnostic caste with relief space in the area of the lesion in which palliative paste will be applied.

3. Fluoride carrier:

Indication:

Used in fluoride gel application to the teeth to protect it from carries (ex: osteoradionecrosis – after mouth preparation for RPD)

Construction:

Made of resilient material (vaccum machine) on the occlusal, buccal and lingual surfaces of the teeth after covering these surfaces with tin foil to allow a space (reservoir) for fluoride

Stents

Mostafa Fayad 5

4. Pedodontic stent:

Indication: This type of stent may be used for young children when there is delayed eruption of teeth. The unerupted tooth surgically uncovered to stimulate eruption to prevent closure of uncovered tissue over the tooth.

Construction: Make impression of the surgical site, poured, wax adapted over the cast and extend to the surgical site to prevent its closure.

Disadvantages: Sudden fall or accident which may lead to sub-luxation or damage to the tooth.

5. Periodontic stent (labiolingual – cosmetic stent):

Indication:

It is used after gingivectomy to cover the exposed root surfaces and to disguise the elongate crown-root appearance seen in wide smile.

The periodontal stent serves both the cosmetic and protective functions.

- It hold periodontal dressing in place after periodontal surgery.

- Used as cosmetic stent or protective prosthesis to cover exposed root surface especially in anterior teeth.

Construction:

1) The stent (labio-lingual design) is fabricated pre-operatively on the diagnostic casts in the area of the contemplated surgery.

2) An accurate alginate impression is made and poured into dental stone.

3) Two layers of modeling wax are adapted over the buccal and lingual surfaces covering the area from the right to the left 2nd bicuspids. The wax extends above the survey line occlusally and extends to the labial and buccal vestibules.

4) Then the stent is processed in clear or pink acrylic

5) The retention of the stent depends upon its extension in the teeth undercuts , wiring of the anterior buttons if necessary, friction with interdental undercut or by wrought wire clasp if needed.

Stents

Mostafa Fayad 6

6. Paraplegic stent:

Indication:

Used as a mouth controlled device for handicapped patient in: feeding –holding things – dial telephone – tying – painting – pushing buttons).

Construction:

Upper and lower primary impression alginate is taken and the upper cast mounted with face bow transfer and the lower cast mounted with centric inter occlusal record at proper vertical dimension of occlusion (VDO).

Wax protrusive record is build up between opposing teeth to increase VDO by 2mm and poly ethylene tube (10-12 inch) is waxed in a hole between 2 central incisors and the wax is processed into acrylic resin, tested intra-orally and adjusted to harmonize condylar guidance of the patient.

Entire thickness of intraoral prosthesis should not exceed 3mm to avoid interference of free way space.

Arch shape metal frame may be embedded in the resin of the oral part to hold extra oral aluminum tube. Active friction grip connector that accepts various attachments may be attached to the stent. These attachments held in various devises which patient needs thus the patient can change these devices himself.

To decrease lever forces on the stent: the stent should have maximum teeth coverage (extend 2mm into the labial surface) to maximize distribution of forces over large number of teeth.

Stents

Mostafa Fayad 7

7. Drainage stent:

Indication: It is used to allow the escape of blood or other tissue fluids from chronic periapical lesions with a fistula, for drainage of infection.

Construction:

1)An impression is made and the fistula is reproduced on the stone cast.

2)A 15-gauge polyethylene tube is inserted in the hole and the labial aspect of the cast is covered with two layers of base plate wax.

3)The waxed stent is processed with clear acrylic resin around the tube

4)If the patient has denture, the stent can be attached to it.

8. Cyst plug:

Indication: In large marsuplized cyst to prevent closure of its opening. i.e. it maintains the potency of the cyst orifice.

Construction:

The cyst is plugged with gauze or wet cotton wool leaving the neck part of the cavity free. Impressions are made and a cast is poured with a small depression is cut representing the cyst neck.

The plug should have a labial and buccal flange, to prevent falling of the plug deep into the cavity. Acrylic buccal flange extend into cyst cavity but not reach full depth to not interfere with cyst wall as cyst decreases in size. Buccal flange extend to buccal sulcus to prevent falling of the plug deep into cyst cavity. Buccal flange also help the patient to remove the plug.

Gradually reduce the depth of acrylic plug as cyst decrease in size until complete filling of the cyst cavity.

If the patient has a denture, the plug will attached to it.

Stents

Mostafa Fayad 8

9. Mouth Guard Or Mouth Protector For Contact Sports:

Indication:

Protect teeth and jaws from injury in boxing contact sports.

Protect fixed restoration when surgery will be made under general anesthesia.

Construction:

Upper and lower primary alginate impression is made and the casts mounted on the articulator.

3-4 mm thickness of resilient material as (plastic sheets of vacuum machine- silicone – polyvinyl rubber) adapted to the upper cast (to be stable, retentive and not interfere with tongue) and cover labial and occlusal surface, border trimmed, finished and smoothed.

The material covering the occlusal surface should be about 3-4 mm to be able to absorb the impact. A wide variety of materials can be used; soft cured material that is applied by a brush in layers or silicone sheets that are adapted to the cast by using a vacuum machine and the excess is trimmed by sharp scissors.

10. Oral screen:

It is an intra-oral acrylic resin stent that is worn usually at night and is bounded by the lip and cheek laterally and by the teeth medially

Indication:

Stimulate nasal breathing.

Stents

Mostafa Fayad 9

It may also be considered as an orthodontic appliance for protruded upper incisor teeth through the pressure applied.

Prevent thumb sucking-prevent lip biting.

Construction:

Alginate impression including the reflection of the buccal sulcus of both jaws are made, casts are mounted on the articulator at correct centric occlusion or centric relation.

2 layers of wax are adapted to the labial surface upper and lower teeth and extended to the depth of the sulcus , processed into clear acrylic resin, it should not interfere with labial frenum or muscle attachment and all pressure areas on attached gingival and movable tissues are relieved.

11. Stent for vestibuloplasty (Stents For Plastic Surgery Of Alveolar Ridge):

Indication:

Used in conjunction with surgical deepening of the mucobuccal vestibule and for holding mucous membrane and skin graft (Vestibulo-plasty).

Reposition the muscle attachment and prevent its reattachment at higher level near the crest of the ridge during healing period after sulcus deepening.

Protect and immobilize the graft, prevent hematoma formation, decrease ischemia of the graft, help the graft to takes, carry medications, make the patient more comfortable.

Construction:

Modification of the ridge and sulcus depth is made on the cast after consultation with the surgeon, modified cast is waxed, flasked and processed into clear acrylic resin (to permit seeing of the pressure area in the mucosa) which is overextended to the new sulcus depth.

If the graft is used it is placed on the stent with its raw surface facing upward.

The stent may be lined with the soft liner, immediately fitted after surgery, may be wired to the ridge if required ( circumferential wiring) and kept in mouth for few weeks till complete healing.

Stents

Mostafa Fayad 10

A similar stent may be designed to facilitate healing after removal of exostosis, palatine and mandibular tori and enlarged median palatine raphe.

Old denture may be modified by extending its border with self cure acrylic resin on the modified cast and used as a stent for vestibuloplasty.

12. Palatal stent:

Indication:

Cover the palate after palatal surgery as (palatal mucosal graft- removal of papillary hyperplasia - torus platinus) to protect the healing surface and apply medications.

It is used to apply pressure to soft tissue after surgery to facilitate haemostasis, healing, prevent collapse and protects the healing of raw surface of the palate.

Construction:

Primary maxillary alginate impressions used to make diagnostic cast before surgery, remove torus platinus or palatal hyperplasia from the cast.

Stents

Mostafa Fayad 11

Acrylic plate is made on the modified cast to cover the palate and wrought wire clasps are made on the teeth for retention.

After surgery, the stent is lined with tissue conditioner and placed on the palate , left in mouth till healing occurs.

If upper complete denture is present it is used as a palatal stent.

13. Stent for Epulis fissuratum:

Indication:

Maintain sulcus depth and prevent obliteration of the sulcus due to fibrous tissue formation after removal of epulis fissuratum.

Construction:

Primary maxillary alginate impression used to make diagnostic cast before surgery, remove the epulis fissuratum from the cast and acrylic plate is made on the modified cast to the proper sulcus depth.

After surgery, tissue conditioner applied to the stent till healing occurs.

If the old denture present it may be used as a stent after modification of its border.

14. Stent for resected maxilla: (Immediate surgical obturator)

Indication:

Carry medications and dressing to the surgical site to improve healing and decrease wound contamination (act as a matrix).

Carry skin graft to the surgical site to improve support, stability and retention of the obturator (compound used on the stent to support the skin graft).

Restore normal palatal contour and allow the patient to speak and swallow normally after awaking from anesthesia.

Allow early removal of nasogastric tube.

Stents

Mostafa Fayad 12

Improve patient psychology: restore patient self image and allow the patient to function normal with society.

Construction:

Look in immediate surgical obturator.

15. Stent for lip and check support:

Indication: Support lip and check in

Facial nerve paralysis (Bells pulsy)-

Mid facial defects (resected anterior maxilla and upper lip and nose)

These diseases affect speech by decrease valve seal mechanism of articulation of orbicularis oris muscle and buccinator muscles which lead to sagging of muscles of check, lip and corner of the mouth on the affected side and abnormal pull of muscles toward intact side and difficulty to control saliva (saliva dribbling).

Construction:

Open looped half rounded wire (hook) attached to the buccal surface of maxillary RPD at premolar area and covered with acrylic resin to support upper lip and the corner of the mouth.

After frame work of RPD casted, the wire loop covered with wax to produce the desired lip support, then the wax replaced with acrylic resin.

Retentive mesh work instead of wire loop may be used in the area of premolars, modeling compound used to produce desired lip support then replaced with acrylic resin (advantages: improve facial sagging, more esthetic, improve labiodental sound more than wire loop).

16. Stents for implants:

a. Stent for surgical implant placement:

Indication:

It is used during the first stage surgery to aid in properly positioning and angulating the guide drill, so that the fixture can be placed to insure optimum esthetics for the prosthesis.:

Stents

Mostafa Fayad 13

It determine site of implant placement and implant angulations especially in the anterior maxillary region.

Construction:

RPD:

A) clear acrylic resin stent perforated at implant site.

B) Vacuum formed stent with holes prepared at implant site and it should have positive tissue stops to be firm, stable during surgery.

CD: old denture may be used as surgical stent with holes prepared at proposed implant sites.

b. Stent for implant imaging: ( radiographic stent, radiographic measurement template , diagnostic Stent)

Indication:

The use of pre-surgical measurement splints has been an accurate cost-effective means of determining various bone dimensions. It is used in detection of bone quantity and bone quality at site of implant placement.

Construction:

Stents

Mostafa Fayad 14

Study casts should be mounted on a semi-adjustable articulator. A clear acrylic splint is fabricated to extend over the edentulous areas of the arch where implant placement is anticipated.

The intended implant site should be marked on the cast. A compatible bur is used to create a slight depression in the acrylic splint.

A 5-mm precision stainless steel ball bearing is placed mesial and distal to the intended implant site. The ball bearing is secured with one drop of super glue. Once the ball bearing is secured, the entire splint is placed in the oral cavity and a panoramic radiograph is obtained.

The ball bearing image on the radiograph is measured with a millimeter gauge to determine the distortion factor of bone in a vertical fashion. If the 5-mm ball bearing now measures 6 mm on the radiograph, a 20% distortion factor is present. Therefore, for each multiple of 6 mm, or fraction thereof, three is only 5 mm of available bone for placement of an implant.

In a similar fashion the splint can be maintained in the oral cavity and an occlusal film may be exposed to obtain a guide as to the buccolingual or horizontal dimension of bone in the area of the intended implant site.

In the totally edentulous mandible a straight lateral radiograph will also provide knowledge of bony dimension at the midsymphyseal area.

(a) Poly vinyl stent: modified by filling the teeth at implant site with radio-opaque material as barium sulfate – ball bearing – metal cylinders (tubes).

(b) Processed clear acrylic resin: holes drilled in teeth and filled with gutta-percha.

(c) Acrylic stent contain radio-opaque teeth.

17. Occlusal stent see later

18. Radiation stents: (prosthesis for radiotherapy)

Stents

Mostafa Fayad 15

19. Trismus stents:

20. Speech rehabilitation aid.

21. Snoring

B. Extra-oral stents:

1. Extra oral radiation protective stent:

Function

Protect extra-oral organs from effect of radiation ex; basal cell carcinoma of eye lid- seqamous cell carcinoma of lip.

Construction:

Lead mask cover most of the face, fenestrated for passage of radiation beam. At least 3-4mm thickness lead covered with acrylic to prevent scattered radiation which is harm full to adjacent tissue.

2. Stent for neck scar: (burn stent)

Function:

Neck burn cause extensive scar formation after healing leading to disfigurement so surgery needed to release scar band and place split thickness skin graft that should be closely attached to the tissues by custom made stent in order to ‘takes’ and decrease formation of hypertrophic scar again.

Construction:

Primary alginate impression is taken to the burned neck which should extend beyond the margin of the graft, if the burn extended to the nares oral tube is used to maintain air way.

Impression is casted and 2 layer wax spacer are applied on the cast to provide a space for the soft liner to be applied inside the stent. Wire hooks are made and self cure acryl is applied on the wax spacer to produce the stent.

Stents

Mostafa Fayad 16

Holes drilled in the stent to make mechanical retention of the soft liner which support the skin graft.

Stent secured in place with loop tape attached to the wire hooks, worn 24 hours/day and removed only to exchange the soft liner till complete healing occurs.

Electrical burns to the oral commissures are the most common type in children. Contraction of wound margins does not usually begin until about 5 days after injury. The use of stent or splint therapy before the start of wound contraction minimizes post burn scaring and the development of micro-stomia.

3. Stent for nasal defect: (temporary nasal prosthesis)

Function:

Worn 3-4 weeks after surgery to improve patient appearance till complete healing of the surgical defect then definitive nasal prosthesis made.

Construction:

It is made of heat cure acrylic resin and lined with tissue conditioner and its retention with medical grade skin adhesive.

Stents

Mostafa Fayad 17

Impression to the defect is made with thin alginate (by adding water) with patient in upright position to avoid distortion of the tissue bed, block nasal cavity with gauze to prevent entrance of impression material, impression poured to produce the cast.

Wax pattern is made and processed into heat cure acrylic resin of suitable color with smooth transition between stent margin and adjacent tissues, the inner surface should be hollowed to decrease the weight.

4. Nasal stent:

Function:

Support nasal cartilage transplant during healing of normal nasal deformity in cleft lip.

Decrease scar contraction following skin graft to the nostril.

Widen nostril in burned patient prior to graft procedure.

Restore nasal air way passage if obstruction occurs.

Construction:

Impression with green stick compound is taken to the nostril and poured to produce a cast, wax pattern is made then processed into clear acrylic resin.

The acrylic resin stent is hollowed to maintain air way and tinted with intrinsic stain as skin color to be less noted by eye.

In case of enlarging nasal air way use series of stents of increasing size or use expandable nasal stent (have orthodontic expansion screw in the lumen of sectioned stent).

Stents

Mostafa Fayad 18

Modeling plastic is used to gradually develop the desired contours of nares.

5. Auditory stent:

Indications:

In surgical reconstruction of external auditory meatus.

mastoid surgery in patients wearing hearing aids.

protect swimmer from chronic ear infections.

Allow anasethiologist to prolong monitor the patient during extensive surgery.

Construction:

It is made from acrylic resin, polyvinyl-silicone.

Cotton wrapped around dental floss and inserted in external auditory meatus leaving 3mm of floss exposed.

Free flowing alginate impression is loaded into a syringe and injected into the meatus and ear pinna. The impression is poured, floss removed.

Mold splitted into 2 halves, lubricated with petroleum jelly and filled with acryl or silicone, extend beyond ear pinna to facilitate orientation and tinted with the color of skin.

Stents

Mostafa Fayad 19

6. Oro-facial plug:

Indication:

To plug skin fistula resulted from infection or done dehiscence which lead to opening on the outer akin and dribbling of saliva.

Construction:

Impression alginate is taken to the opening, cast is scrapped at the site of the fistula, wax applied to the defect and flanges made for retention, wax processed into silicone rubber, tinted, flushed with adjacent tissues for esthetics until corrective surgery is made.

Stents

Mostafa Fayad 20

Occlusal Splint or Stent (bite plate, bite guard, bite splint)

A bite splint (also called bite plane, deprogrammer, intraoral orthotic, night guard, occlusal splint) is a removable appliance, usually fabricated of acrylic or composite, most often designed to cover all the occlusal and incisal surfaces of the teeth in the upper or lower jaw.

Objective

1- Protect the TMJ disks from dysfunctional forces that may lead to perforations or permanent displacements.

2- Improve jaw-muscle function and to relieve associated pain by creating a stable balanced occlusion.

Indication:

1) It is a diagnostic appliance e.g. for evaluation of the required increase of vertical dimension in case of severe attrition of the teeth.

2) As night guard in patients with parafunctional habits e.g. bruxism and clenching. For Prevention of tooth surface loss. Patients who are prone to nocturnal bruxism should routinely wear occlusal splints at night.

3) Pre-restorative stabilization

4) Creating space to restore worn anterior teeth

5) Protection of new restorations from parafunction habits

6) For the treatment of temporomandibular joint pain dysfunction syndrome

- It may have smooth flat occlusal surface for relaxation (muscle relaxant splint).

- It may provide relief of acute symptoms by repositioning the condylar head within the glenoid fossa (anterior repositioning splint).

The effect can be direct by changing the relations between the intracapsular TMJ elements or indirect by affecting the muscles’ working conditions.

Stents

Mostafa Fayad 21

Types of stent: Bite splints can be classified according to:

• Material used for fabrication.

• Location of placement.

• Design of area for contact with opposing teeth.

• Effects on condylar position at clenching.

• Specific purposes.

Smooth flat occlusal surface for relaxation by allowing contact of all opposing teeth.

Indentation and / or ramps for mandibular reposition device.

Soft device is more comfortable to patient with bruxism or clenching to distribute the pressure equally.

Design of area for contact with opposing teeth.

Splints may for instance be classified as follows:A) Splints which make balanced contacts with all opposing teeth at jaw closure

a) Causing a minimal increase of vertical allowing the patient to close with a “hinge axis movement”. That is the rotation centers of the condyles are not changed.b) causing a more than minimal increase of the vertical but still without changing the condyles’ rotation centers.c) Increase the vertical and causing a translatory movement of the condyles at the final part of closure (thus changing the rotation centers).

B) Splints that make contact only with parts of the opposing arch at jaw closure.

a) Contacts only with the anterior teeth in the opposing arch.b) Contacts only with the molar and premolar teeth in the opposing arch.

Splints in groups A.a, b have a minimal risk of causing permanent changes in occlusion. Splints in groups A.c and B can cause such changes if used for longer than a few (4-6) weeks. Examples of Group A.c splints for instance, are

Stents

Mostafa Fayad 22

the so-called repositioning splints. Long term use of splints that make contact only with some of the opposing teeth may cause serious irreversible changes in the occlusion. Splints where the only contacts are with the incisors may cause an anterior open bite. Splints with contacts only in the molar regions may cause intrusion of the teeth there.

a- Splint MaterialIn the past several metal materials were used to fabricate bite splints

including gold, silver, - even lead.Most splints are now made using heat cured acrylic. Splints can also be

made in soft acrylic , vacuum-formed soft vinyl or using light cured composite.a) heat cured acrylic

The material of choice is laboratory-processed acrylic resin. It is a reasonably hard material which may be easily adjusted and is durable enough to serve as a protective night-guard.

b) Soft acrylic splints

They are usually made for the lower jaw, can be made quickly by the dentist

indicated for short time use in patients with acute pain and/ordysfunction symptoms caused by muscular hyperactivity or acute trauma. This type is also indicated in children with deciduousteeth if they have signs and symptoms of severe bruxism.

Soft acrylic splint for daytime use are indicated in patients when night time use of a hard splint is not sufficient to relieve the symptoms or break the habit during daytime. A soft splint can be used during daytime to help in breaking the parafunctional habit, either alone or used in one jaw with a conventional hard splint in the other.

b) Resilient vacuum-formed vinyl splints

they are of limited use. Although quick and economic to make they are soon destroyed by determined bruxers.

Stents

Mostafa Fayad 23

Their resilient surface is not amenable to the production and maintenance of the stable occlusion necessary to achieve muscle relaxation.

c) Hard metal alloys:

The use of hard metal alloys such as cobalt/chrome to cover

occlusal surfaces is highly inadvisable as it will result in increased

wear of the opposing teeth.

b- Location

Maxillary or mandibular splints?

Providing the requirements of full occlusal coverage, posterior stability,

anterior guidance and use of an appropriate material are met, it matters little

whether a splint is made on the maxillary or mandibular arch.

In Class I and II incisor relationships it is easier to produce an ideal occlusion

on a maxillary appliance while the converse is true in Class III situations.

Maxillary splints.

Without specific reasons for a mandibular placement, a splint

should be made for the upper jaw.

Many clinicians find it easier to make a stable splint with good

retention and adequate cuspid guidance in the upper jaw.

A maxillary splint can be made “invisible” in most cases if

extension onto the facial surfaces is avoided.

Extension onto the facial surfaces of the incisors should be avoided.

Besides not being esthetic it may prevent adequate lipseal.

Breakage of lipseal may lead to mouth breathing during sleep with harmful

side effects. Extension onto the incisal facial surfaces is not needed for

retention which can as well be obtained by extension onto the buccal surfaces

Stents

Mostafa Fayad 24

of molars and premolars. Such coverage is not visible and does not prevent

lipseal.

If not enough retention can be obtained that way a couple of simple clasps

may be added.

Mandibular splints

In deep curve of Spee or substantial loss of mandibular teeth it may

be preferred, to make a mandibular splint .

If the splint is to be used during daytime it may be preferred, for

esthetic reasons, to make a mandibular splint which may be less

visible.

However it encroaches more on the space normally occupied by the

tongue.

In patients with horizontal overjet, a mandibular splint has to be

extended in the anterior direction to obtain anterior support. Such

a“buttress” may interfere with normal lipseal and irritate the lower

lip thereby triggering parafunctional activity in the orbicularis oris.

Anterior contact may not be possible in all cases with large

horizontal overjet.

If teeth are missing the splint should be made for the jaw with the fewest

teeth (in the jaw where most teeth are lost) . If molars and premolars are

missing in both jaws, it may be advisable to make both an upper and a lower

splint or to first restore occlusion in at least one jaw with prosthodontic

reconstruction.

c- Usage

There are no fixed rules for how long patients should continue to use splints.

However, with few exceptions, non-conservative splints that often have to be worn 24

Stents

Mostafa Fayad 25

hours a day should not be used for more than 4 to 6 weeks to avoid the risk of irreversible

occlusal changes.

Bite splints should be looked on as temporary solutions to be used only until a

final diagnosis has been made and a curative treatment has been successfully performed.

Unfortunately, it is some-times not possible to reach those goals; in those occasions only

should, a dentist can encourage a patient to use a splint indefinitely.

Patients who have conservative bite splints prescribed because of parafunctional

motor activities like bruxing, clenching, and tongue pressure mainly use their splints only

during sleep. However, those who cannot control such habits when awake might need to

use the splint during the day also.

Construction:

Upper and lower impressions are made. Stone casts are poured and mounted in centric relation. The articulator is opened slightly for the required thickness of the splint.

The upper cast is usually used for waxing the splint. A base plate is adapted to cover the incisal and occlusal surface surfaces of the teeth till the middle of the second molars distally. The splint extends 1-2 mm on the facial surface and covers the whole palatal surface of the teeth and 1-2 mm above the gingival margin.

The splint is processed in clear acrylic resin.

Soft rubber material may be used in splint construction. A rubber sheet is adapted over the cast by vacuum machine.

Most used types of splints.

A Michigan (MI) type splint ( plane splint with cuspid guidance) is usually placed in the upper jaw covering all the maxillary teeth, giving the opposing mandibular teeth balanced, even contacts at habitual closure.

Stents

Mostafa Fayad 26

In a MI splint all mandibular teeth, except the cuspids, are discluded at protrusive and lateral movements. This type is recommended in patients with signs and symptoms of jaw muscle hyperactivity (bruxism, clenching). If teeth are missing, the splint is usually made in the jaw where most teeth are lost. If molar support is lost in one jaw only, the splint should most often be made in that jaw with a saddle extended where teeth are missing.

Some patients may feel that a mandibular splint is uncomfortable and a maxillary splint may then be tried in spite of lost mandibular occlusal support.

Cuspid Guidance. A cuspid guidance is created to provide a rise in lateral and protrusivemovements, so that the only contacts are between the mandibular cuspid apex and the cuspid guidance.

The mandibular cuspid should slide on a flat area inclined only in the sagittal plane during protrusive and in the coronal (frontal) plane during lateral movements.

Ideally cuspid guidance should be on the apex of the mandibular cuspid. It may be on the mesial cusp ridge of the mandibular cuspid during protrusive movement or on the distal cusp ridge of the mandibular cuspid during lateral movement. No guidance should be on the axial surface of the mandibular cuspid! There should be no posterior contacts in protrusive and balancing and no incisal contacts in protrusive.

In the natural dentition a slide from CR to CO takes place mostly with a vertical and sometimes also with a lateral shift in the mandible’s position. One important goal in the fabrication of a plane splint is to create an area around the contacts at habitual closing which makes it possible for the mandibular teeth to move from CR to a CO position without such vertical or lateral shifts. It is considered by many clinicians that part of the beneficial effect of the plane bite splint is because of the elimination of such shifts.

Plane splints without cuspid guidance. For esthetic reasons some patients may prefer to have splints without cuspid guidance. It is easier to make a plane splint “invisible” if that feature is excluded.

A common feature to the above two types is that balanced contacts with all opposing supporting cusps and the incisal anterior teeth edges should be achieved. There are, however, some clinicians with long time experience from treating TMD patients who claim that better results are achieved if the anterior contacts (incisal areas) are very light or removed.

Stents

Mostafa Fayad 27

Bite splint according to Shore. This splint has a design similar to the plane splint but does not extend onto the facial or buccal surfaces of the teeth, and covers the entire palatal area. It may be preferred by some patients who need to use the splint also during daytime, for esthetic reasons, because it can be made less visible. In some patients with parafunctional tongue activities, such a palatal extension may be felt more comfortable. A Michigan splint can easily be changed into this type by removing facial and buccal extensions, adding palatal cover and, if needed, securing adequate retention with

clasps.

Relaxation plate (Sved plate). Only the opposing anterior teeth make contact with this splint.

It is not recommended if the patient has acute pain in the TMJ or feels pain or soreness at palpation of those areas. It is easy to change a plane splint into a relaxation plate or vice versa. It is recommended that the relaxation type is tried in patients with acute or chronic muscle pain if the plane splint is without effect. It is usually placed on the upper teeth with an incline in the anterior part giving contact only with opposing cuspids and incisors. It should be used only during nighttime and not more than 10- 12 hours/day. There is a risk for intrusion of teeth, which has to be explained to the patient before splintdelivery. Regular checkups are, as always, important.

Mandibular splint with lingual bar. Unlike the Sved plate, this type is supposed to be used during daytime. Its primary purpose is to help patients who can not control oral parafunctional activities when awake and do not feel comfortable with a splint of the Shore-type. The splint does not cover the cuspids or the incisors and should have balanced contacts in the premolar and molar areas both in CO and in CR. It is most often adjusted to achieve group contact on the working side at lateral movements. Precautions are the same as for the relaxation type splint.

Repositioning splints. Plane bite splints increase the vertical but should not in any other way affect the position of the mandible when habitual clenching occurs on the splint. Repositioning splints guide the mandible into a different position at closing, which is supposed to facilitate repositioning of the disk and reduce the load on retrodiscal pain sensitive areas. These splints are sometimes indicated for short-term use to keep arecaptured disk in a normal superior position for instance when a displaced disk has been recaptured by manipulation.

Bite splint with a pivot. This type was introduced by Krogh-Poulsen about 40years ago and was supposed to be helpful in patients with disk displacement. The proposed effect is

Stents

Mostafa Fayad 28

that the condyles are pulled downwards upon clenching on the pivot, thereby relieving traumatic load and giving the disk freedom to reassume a normal position. Today it is seldom used because most patients find it uncomfortable.

Cap splints. A cap splint can be described as an intermediary between a splint and a bridge. It is useful for temporary reconstruction before final decision about design, vertical dimension, etc. It is often made in metal with the occlusal surface in hard acrylic.

Combination splint/partial denture and splint/orthodontic appliance. Missing teeth can easily be replaced by adding artificial teeth to the splint. A Shore splint may function as a temporary partial denture by adding artificial teeth. Another fringe area exists between occlusion and orthodontics.

There are numerous combinations of splint and orthodontic appliances. An ‘invisible retainer’ may simultaneously function as a soft acrylic splint.

Sved plate. Only the opposing anterior teeth make contact with this splint. It is recommended for patients with acute or chronic muscle pain if the plane splint is ineffective. The Sved plate is usually placed on the upper teeth. It is mostly used only at night and not more than 10 to 12 hours a day. There is a risk for intrusion of teeth, which has to be explained to the patient before delivery. As always, regular checkups are important.

Gelb splint. The Gelb appliance is made in the lower jaw, covering only the premolar and molar teeth. It is used to correct mandibular displacement, reduce TMJ dysfunction and oral/facial pain, and to provide occlusal stability with the patient's natural dentition serving as the anterior guid-ance. Some dentists fear that this splint can cause intrusion of the posterior teeth. The originator claims that what seems to be an intrusion is actually a postural change because of a corrected jaw imbalance.

Distraction splints. The pivot splint was introduced by Krogh-Poulsen about 40 years ago and was supposed to be helpful in patients with disk displacement. The proposed effect is that the con-dyles are pulled downward upon clenching on the pivot, thereby relieving traumatic load and giv-ing the disk freedom to reassume a normal position15 . It is seldom used today because most pa-tients find it uncomfortable. The distraction splint, used by Pedersen et al to achieve a similar ef-fect, has been tried successfully to reduce the destructive effect of juvenile rheumatoid arthritis on internal TMJ structures.

Splints for protection of oral tissues. The most common reason for making a splint is to protect the teeth from excessive abrasion in bruxers. Several variations of splints are

Stents

Mostafa Fayad 29

designed to protect cheeks and the tongue in patients with oral parafunctions (such as cheek biting or tongue thrust). These patients may benefit from a splint with extensions or enlargements designed in a way that keeps the cheeks from being pinched or the tongue from pressing against the lingual surfaces of the teeth.

Combination splints. Missing teeth can easily be replaced by adding artificial teeth to the splint. A Shore splint can function as a temporary partial denture by adding artificial teeth. There are nu-merous combinations of splint and orthodontic appliances. A removable bionator appliance can act both as an orthodontic and as a repositioning appliance. An “invisible retainer” can simultane-ously function as a soft acrylic splint.

Others. Patients with oral parafunctions like cheek biting, tongue thrust, large diastemata, etc. may benefit from a splint with extensions or enlargements designed in a way that will keep the cheeks from being pinched or the tongue from pressing against the lingual surfaces of the teeth.

Bruxism

Signs of bruxism

Masseter hypertrophy

Non-functional wear facets

Stents

Mostafa Fayad 30

A maxillary MI Occlusal Splint is the type most often used

Mandibular advancement splints to be used for repositioning a disk and keep it in a normalized position

Stents

Mostafa Fayad 31

Holder for the articulating paper.

Use a “horse shoe” formed holder for the articulating paper. If you do not have that type - use type B – not type A.

Radiation

Mostafa Fayad

Radiation Therapy

The common treatment of neoplasm is surgery and/or radiation. A tumor can be

destroyed by radiation if the dose is sufficient and is within the tolerance level of the

adjacent normal tissues. Post radiation sequels are significant and may result in total

morbidity.

Irradiation may be delivered to diseased tissue with internal or external madea or

both, depending on location, sensitivity of the tumer being treated, type or internal

sources include intracavitary cones or cylinders positioned by a carrier appliance.

Interstitial tubes, needles, seeds or threads that contain radiation sources may be

implanted. The use of colloidal suspensions, solutions, intra-vascular injections and intra

cavity instillations are less commonly. External radiation sources are more widely used.

Definition of some basic terms

Roentgen: the unit of exposure

The rad: the unit of absorbed dose or energy absorbed in the depth of the material.

Since it is difficult to meassure rads directly, exposure is measured in roentgen, and

by means of conversion factor the number of rads is calculated using the following

equation:

rads per minute (absorbed dose rate = roentgens per minute (output) X depth dose in

roentgens X conversion factor (F)

KV : Operating kilovoltage of the machine.

HVL: Half-value layer; the filtration needed to reduce the beam to one half of its

original value.

TSD : Target-to-skin distance: distance from the radiating source to the patient’s

skin.

Radiation

Mostafa Fayad

SSD : Source -to- surface distance, distance from radiating source to the patient’s

skin.

STD : Source -to- tumor distance; distance from the radiating source to the tumor

Wedge filter: Filter used to modify the treated beam to produce more homogeneity,

specially on curved surface.

- Gy = Gray (standard unit of measure)

- CGy = Centi-gray (1/100 of a Gray)

- 1 cGy = 1 rad (old terminology for dosage)

Types of Radiation

1- Waves:

a) Short waves → deep penetration → more damage.

b) Long waves → less penetration → less damage.

2- Beams.

3- X-rays.

4- Implants (Radiation Implant seeds).

Types of Radiation Therapy Techniques

- External Beam therapy: X-rays (photons) and electrons (particles)

- Interstitial therapy: Radioactive needles and seeds

- Intra-cavitary therapy: Radioactive needles, seeds, wires, etc.

Radiation

Mostafa Fayad

Effects of radiation :

Although this treatment modality is effective in the management of selected

patients and disease entities. Its curative dose of whatever type is often associated with

unwanted destruction of normal tissue, and this risk must be accepted by the patient if his

life is to be saved.

The primary effects of radiation occurs within the nucleus which is extremely

more sensitive than the cytoplasm. The complication of radiotherapy are not limited to

the immediate postoperative period; in fact the more seious complication occur 12

months or more after therapy. The hazered of the radiation may affect the offspring,

perhaps for several generation.

There is a direct proportion between radiation absorption and the density of the

tissue being irradiated. The density of the bone is 1.8 times that of the soft tissue. Thus it

would absorb more of the delivered dose than would soft tissue.

However, the ways in which energy is dissipated along the path of an exciting

photon or gamma ray is important for the biologic effect produced in the irradiated

tissues and for control of such irradiation, its direction, definition and manipulation by

the radiotherapist , the number of fractions, interval of delivery, and total dosage

administrated must be taken into account.

The biologic effectiveness of supervoltage therapy is somewhat less than that of

the orthovoltage range. When supervoltage radiation is used, the course of therapy is

commonly split into two halves, with approximately a one-month interval between. This

approach enables the normal tissues to recover from the effects of the first half before the

second phase is begin, which is then better tolerated.

Cobalt-60 is a satisfactory radiation source for therapy. The radiation has a skinsparing

effect and decreased absorption in bone, in comparison with conventional units. The

treatment fields can be well defined, and scatter of rays is in a forward direction instead

Radiation

Mostafa Fayad

of laterally. Late atrophy is rare with Cobalt-60 therapy. The linear acceleration radiation

up to 10 Mev. (million eletron volts) has decreased absorption in bone, but above to Mev.

Absorption increases. So the electronvoltage (in Mev) can be selected according to the

depth of the lesion.

Under 3,000 cGy

– Mucositis, candidiasis, xerostomia & dysgeusia begin

Over 3,000 cGy

– Xerostomia (permanent) and taste dysgeusia

– Altered saliva (thick, more acid, changed flora)

Over 5,000 cGy

– Trismus

– Concerns for osteoradionecrosis

Over 6,000-6,500 cGy

– Significant concerns for osteoradionecrosis

Radiation

Mostafa Fayad

Factors affecting the rate of damage:

1- Radiation dose :The higher the dose the higher the damage.

2- Energy source : Radiation by external source may cross normal structure before

reaching the tumor, thus affecting theses structures. While, if radiation is implanted,

the radiation is more confined to the area.

a) External source ( Increase damage to adjacent structure ).

b) Interstitial radiation therapy ( e.g. needles – tubes – wires – small seeds ).

3- Type and sensitivity of tissues to radiation: Embryonic, immature or poorly

differentiated cells are more easily affected than differentiated cells of the same

type.

4- If radiation is in fractions, recovery may occur, when the rate of delivery is small.

5- The greater the mass of irradiated tissue, the greater the damage.

6- Radical neck dissection before radiation reduces blood supplies and increases the

damage.

7- Pretreatment performance status,

8- Pretreatment periodontal condition.

9- Mass of irradiated tissue: increase the mass exposed to radiation → increase damage

of tissue.

10- Obesity: increase the obesity → increase the damage.

11- Age of the patient: increase the age → increase the damage.

Radiation

Mostafa Fayad

Effect of radiation on different tissues:

The primary effects of radiation occur within the nucleus since it is 100 to 1000

times more sensitive to radiation than the cytoplasm.

A- oral mucosa

Immediate Effects: Buccal mucosa shows initial erythema, reduced

keratinization, vascular dilatation and inflammation of the submucosa. It

appears 2 to 3 weeks after the start of therapy and reaches its peak towards

the end of therapy.

Erythema of the oral mucosa is usually begin 10-14 days from the beginning

of the treatment and subside shortly after therapy has been completed. The

capillaries become congested and may obstructed later by thrombasis. The

oropharyngeal mucosa may be covered with whitish painful membrane.

Changes in the oral flora with overgrowth of candida albicans may occur.

White patches appear on the lips, cheeks and tongue and overgrowth of

Candida albicans is a common complication, which may be due to the

imbalance in oral flora. Healing is usually rapid and is within 2 to 3 weeks

after completion of therapy.

Delayed effects: Severe mucositis in the soft palate, mucosa of the

hypopharynex, floor of the mouth, buccal mucosa, and base and dorsum of

the tongue.

B- Skin:

Immediate effects on skin are mainly erythema; redness and swelling that

resemble thermal burns.

Radiation

Mostafa Fayad

The skin becomes erythemature, edematuse and dry- Desquamation of

epithelial. Denudation of the surface and epilation is usually noted. These

changes may lead to necrosis of the soft tissue

Delayed effects on skin Changes may go on from erythema to ulceration

and necrosis. The epithelium becomes thin atrophic and superficial blood

vessels become telangiectatic or occluded.

Ulceration on the corner of the mouth may occur (angular cheilitis).

C- Tongue

Immediate effects on tongue The tongue becomes more sensitive to spicy,

hot and cold foods.

Delayed effects on tongue: Taste buds show signs of degeneration, atrophy

and the patient experiences partial or complete loss of taste that is

accentuated by reduced salivary outflow.

D- Eyes

Immediate effects on eyes : Eyes if left unshielded, irritation conjunctivitis

may occur.

Delayed effects on eyes: Eye effects include damage to eye lens and

development of cataract.

E- Salivary glands

The amount of saliva is decreased and became thickened due to interstitial

edema and duct obstruction. Loss of appetite may result due xerostomia and

falling of pain during swallowing. Also reduction in the pH of saliva (3.5)

occurs.

Radiation

Mostafa Fayad

Prosthetic effects: the patient can't tolerate his prosthesis due to more

friction during function as saliva acts as an effective lubricant. Retention is

compromised, as the peripheral seal may be difficult to obtain.

F- Taste

Alteration of the taste sensation may occur in the first days of irradiation

therapy due to congestive changes of the taste buds accompanied by

modifications in the quality and quantity of saliva. These alteration are

usually not permanent unless doses of 6.000 rads or more are used.

G- Neuromuscular function

Temporomandibular joint and masticatory muscles are allover affected by

radiation. Trismus ma be occured especially after 4-6 months.Regyular

mandibular exercises before and after therapy reduces the incidence of

trssmus.

H- Teeth and periodontium

Radiation cases often occurs at the cervical area of teeth. This finding may

be due to decalcification of teeth of teeth. and changes in the quality

(increase acidity) and decreased quantity of salivary secretion associated

with radiation. The teeth became hypersensitive to temperature change and

sweets. Changes in periodontal ligament and feeling elongation of the teeth.

In growing teeth the development may be partially or entirely inhibited by

irradiation. In children partial anodontia or dwarfing teeth may be noted

due to injury to the tooth germ.

Decalcification of teeth due to radiation (radiation caries). The vascularity

of the pulp tissue is reduced leading to fibrosis and atrophy.

Radiation

Mostafa Fayad

Fibers of the periodontal ligaments are disoriented, thickened, decreased

vascularity and are more prone to infection, which may be associated with

bone resorption and eventual loss of teeth.

I- Osseous Tissue

maxillary bone effects is more than the mandibular due to more radiation

absorption → osteoradionecrosis.

Bone is relatively resistant to radiation, but a heavy dosage can upset the

normal balance between bone formation and resorption, and cause

limitation or obstruction of the blood supply. These disturbance reduces the

ability of the tissues to withstand trauma and infection and thus increases

the opportunity for osteomyeltis and necrosis. Bone growth may be limited

or stopped due to destroying of osteoblasts and osteoclastes.

Osteoradionecrosis may be develop due to loss of bone vitabity caused by

sclerosis of the periosteal and associated vessels. The pathogenesis is not

known, but three factors are invloved: radiation, trauma and infection.

Osteoradionecrosis is the major complication of irradiation to the head and

neck. Osteoradionecrosis is more common in mandible than maxilla due to

a diminished in frequently unpaired mandibular blood supply.

The effect of irradiation on bone is often become manifest for years after

treatment.

Bone absorbs radiation 1.8 times than does a comparable volume of soft

tissue. The more the bone density the more is the absorption of radiation.

This explains why the mandible absorbs more radiation than the maxilla.

More absorption of radiation coupled with reduced blood supply in the

mandible than the maxilla makes it more susceptible to osteoradionecrosis.

Radiation

Mostafa Fayad

J- Trismus:

Radiation in the temporomandibular joint area and muscles of mastication may

lead to fibrosis 3 to 6 months after the completion of therapy leading to trismus

which result in impaired mastication and limited mandibular movements 10 to

15 mm.

Treatment: includes exercising and the use of dynamic bite opener.

K- Diet:

As a result of reduced salivary output, mucositis, pain during swallowing and

loss of taste occurs. The patient experiences loss of appetite, nausea and

malaise

Weight loss and dyspnea: The treatment is supportive and symptomatic →

saline rinses, systemic analgesics, Nystatin and local anesthesia.

Oral complications from radiation therapy

Radiation changes have a direct effect on rehabilitation of both intraoral and extraoral

defects found in the maxillofacial prosthetic patient. Radiation changes include:

Erythema and tissue sensitivity (mucositis),

Ulcers in the mouth and on the lips,

Fungal infections,

Dryness (xerostomia) of the mouth from salivary gland destruction,

Dental decay from decreased salivary flow and pH changes,

Possibility of infections in the jaws or the potential for osteoradionecrosis from

infection or trauma to irradiated bone.

Hypersensitivity of the teeth,

Radiation

Mostafa Fayad

Dental pulp changes,

Taste loss,

Oral bacterial shift,

Periodontal breakdown

The morbidity of head and neck irradiation, for instance, include xerostomia,

laryngeal edema, trismus, hearing loss, facial hair loss, and loss of taste.

Dental management of irradiated patients

The main objective of dental management for irradiated patients is to preserve the

tissues in the field of radiation. A lot of controversy has existed concerning the

preradiation and post radiation dental treatment alternative.

1- Preradiation treatment

Before the onset of irradiation the patients will require a thorough visual and

digital oral examination and a radiographic ( periapical, penoramic or both) survey of the

teeth and jaws.

It is recommended by the consensus that any malposed, non restorable diseased

teeth.(affected be caries, periodontal disease, periopical pathology) or lie in the field of

radiation must be removed to reduce the possibility of osteoradioneocrosis. Some authers

prefer the prophylactic removal of all teeth, regardless of their condition or location

because patients who are edentulous before radiotherapy are less likely to acquire

osteoradionecrosis.

The surgical procedure must emphasize minimal trauma. A healing period 10-30

days is desirable before beginning of irradiation, depending on the case.

Radiation

Mostafa Fayad

The following must be removed:

1- Teeth in the field of radiation → to avoid osteoradionecrosis.

2- Periodontal involved, badly decayed → should be removed before therapy.

3- Sharp bony specules.

The following must not be removed:

Teeth within tumor to avoid dissemination of tumor cells.

The following could be left:

Teeth of unaffected side if radiotherapist allow that.

II- Post radiation treatment

1- The patients must be seen at frequent regular intervals for examination as early

diagnosis minimizes patient morbidity and entances the effectiveness of treatment.

2- Strict oral hygiene include rinsing and cleaning of the mouth are essential. Trauma

caused by tooth brush should be avoided.

3- The daily use of topically applied 1% sodium fluoride gel is specially made carrier

may reduce the incidence of caries by 30% - 40%. The tooth sensitively may also be

reduced by fluoride .

4- To reduce the pain in swallowing, topical anesthetic solution can be used before

mealtime.

5- In case of xerostomia, the patient is advised to carry a small spray bottle of water all

times to wet the mouth.

6- All patients undergoing postirradiation extraction or surgery should receive prophylactic

antibiotic- at least 1 gram of penicillin daily- for 2-4 weeks postoperatively.

Radiation

Mostafa Fayad

7- Unsloughed bony sequestra should be surgically removed and rough bone is smoothed

with debridement.

1- Conservative, strict oral hygiene rinses with H2O2 or warm saline.

2- Antibiotics and analgesics → in case of infection or pain.

3- Any surgical intervention is contraindicated → massive tissue loss.

4- Prophylaxis against tooth decay (treatment by 10% stannous fluoride application ).

Prosthetic construction for irradiated patient:

Some authors suggesting that removable prosthesis should not be used for

irradiated tissues. Others, however have proposed that after careful evaluation denture

prosthesis can be constructed 6-24 months postradiation.

The period of waiting before construction depends on the site of the lesion, the

radiation dosage and the condition of the mucous membrane and the patient comfort.

Irradiated patients who required obturators began immediately after removal of the

surgical pack. If more conventional types of removable prosthesis are indicated, it can be

constructed after several months to allow for adequate improvement of the oral hygiene.

A symptomatic denuded bone can be covered with a prosthesis. The irradiated

tissues are fragile so the finished prosthesis should be well adapted, stable and retentive.

Trauma caused by ill - fitting denture specially the lower should be avoided.

The use of resilient nonirritating impression materials, stress limiting occlusal

schemes and tooth material are important to reduce tissue trauma.

The patient is instructed to leave the denture out of the mouth at night and for

frequent and longer periods during the day to rest the tissue.

Radiation

Mostafa Fayad

The patient is advised for soft diet and to use more liquids with meals sticky, hot and

spicy foods as well as alcohol and tobacco should be avoided.

a) Prosthodontic treatment:

- Placement of Dentures (Timing):

Denture construction for irradiated patients should made if 12 – 14 months had elapsed

for mucosal healing. Some patient may wait 2 – 3 years before mucosa has recovered

sufficiently to tolerated denture.

- Two groups to consider:

1- Patients edentulous prior to radiation therapy and having denture

experience → new denture can be made after mucositis has resolved.

Denture bearing area should be checked with PIP before insertion.

2- Patients undergoing pre-radiation or post-radiation extraction with

denture after completion of radiation → denture bearing should be

examined contour, irregularity and scar before denture fabrication.

- Success of prosthodontic treatment depends on:

1- Pre-operative data.

2- Through oral examination.

3- Prosthodontic treatment (Non traumatic and non irritating denture).

4- Effective follow up system.

[ I ] Preoperative data:

1- Type and size of tumor. 2- Mode of therapy.

Radiation

Mostafa Fayad

3- Total dose.

4- Data of treatment.

5- Radiation fields.

6- Tumor response.

7- Prognosis of tumor.

[ II ] Oral examination:

1- Routine examination for denture:

- Entire oral cavity should be

examined visually and palpated

for any soreness.

- Appearance of oral mucosa.

- Scarring and fibrosis at tumor site.

- Degree of trismus.

- Salivary function.

- Tori.

- High tissue attachments.

- Enlarged maxillary tuberosity.

- Flabby tissue.

- Abnormal jaw relation.

2- Undercuts are undesirable to engaged, if they are present in field of radiation.

3- Surgery is contraindicated.

4- Post-irradiation symptoms. e.g. pain, Xerostomia and trismus.

5- Patient warned of possibility of osteoradionecrosis.

[ III ] Prosthodontic procedures:

1- Impression:

Radiation

Mostafa Fayad

- 1ry impression: should be made with alginate and not compound.

- Xerostomia: should be treated by using petroleum jelly.

- Border molding: Done by using low fusing wax or heavy rubber base. The lingual

flange shouldn't used to gain more retention and only for stability.

- 2ry impression: should be made with rubber base.

2- Jaw relation:

- Low vertical dimension of occlusion offers low forces and less trismus.

- Centric relation record should be achieved with no trauma.

3- Try-in:

- Modified anatomical or flat teeth should be used to decrease the horizontal forces.

- Denture base should cut away to minimize irritation.

4- Insertion:

- Any roughness or sharp angles should be removed.

- Silicone soft liners may be used to minimize mucosal trauma.

[ IV ] Follow-up:

- The patient follow-up performed daily for about 2 weeks.

- Then patient follow-up performed once every 3 months.

Radiotherapy prostheses

Radiation

Mostafa Fayad

Radiotherapy prostheses are stents used to help the radiotherapist in treatment of oral

malignancies by radiation.

Objective of radiotherapy prosthesis:-

1-It reduces the side effects of the treatment.

2-It protects tissues that are not meant to receive radiation.

3- It increases the accuracy of radiation source and assures that the area of treatment is

the same every time the patient is irradiated.

4-It results in a more cooperative patient since discomfort and injuries are reduced.

5- Enable lowering the field of radiation (protect the parotid gland).

6- Safer for radiotherapist in treatment.

Indication:

Protect or displace vital structures.

Locate diseased tissues in repeatable position during treatment.

Carry radio-active material to turner site.

Recontour tissue to simplify dosimetry.

Positioning of beam.

Requirements:-

1-Comfort: - The patient should be able to wear his prosthesis comfortably while

receiving radiation and allows the patient to breathe easily. All surfaces must be smooth;

a tissue conditioning material may be used to line the prosthesis in contact with sensitive

areas.

2. Minimal weight: The lighter the prosthesis, the better it will be tolerated by the patient.

Radiation

Mostafa Fayad

3. Retention and Stability: The prosthesis must remain in a definite position throughout

the treatment.

4- Suitable strength:The material used should be of suitable strength that resists

breakage; acrylic resin is a suitable material.

5- Easy to repair and clean.

6- Allows visualization of tissues; clear acrylic resin is the material of choice.

7- Easy to be inserted and removed by patient.

8- permitting easy breath

Types:

1- Carrier applicator.

2- Director appliance.

3- Maintaining the structure of the tissues to be treated.

4- Tongue protector (shielding).

5- Prevention of tongue and cheek biting.

6- Positioning of the radioactive source (Dosimentric device).

7- Recontouring tissues to simplify dosimetry.

Types:

a) Radium applicator (carrier):

Use:

Radiation

Mostafa Fayad

Allow administration of pre-calculated dose to inaccessible area.

direct radiation to exact location in treatment of malignancy

Construction:

Primary alginate impression casts the area involved is out lined by

radio therapist base plate (heat – self cure) clear acrylic resin to allow

pressure area to be seen.

Types:

a) Wire carry radium capsule: fixed at 2ends e set cure to plate clone, wire adjusted

so that radiation directed to exact location.

b) Radiation material embedded in play-ethylene tubes: at fitting surface of base and

covered with self cure acryl. Rubber gloves impregnated with lead, protective

shield must be used during radium manipulation for self protection.

c) Soft irradiation applicator (lithium fluoride carrier):

Advantages:

Simple, economic, efficient in irradiation of persistent superficial carcinoma.

Easy to control dose to various parts of lesion, if large does required, simply

remove some seeds

Construction:

Primary alginate impression cast outline surface to be irradiated with a

pencil adapt layer of base plate wax to outline. A line is drawn 1 cm beyond

periphery lesion, strip of beading wax attached to cast at this line, self lure acrylic

resin extend 1cm beyond periphery lesion in all directions. While the wax is soft

hooks attached to it for retention of prosthesis.

Radiation

Mostafa Fayad

Grooves placed along inner surface of prosthesis in which nylon tubes embedded

to average depth 5 mm from inner surface in depth of each groove, tubes are

parallel to each other at interval of 1cm, extend 3-5mm out of the prosthesis.

Nylon ribbon contains radioactive seeds fit within hollow tube, prosthesis attached

by hooks (3 wire hooks) to modified orthodontic head gear maintained

in stable position to deliver desired amount of radiation.

b) Positioning peri-oral cone (Docking device):

Function

Positioning perioral cone and direct beam of radiation in exact

position in repeated exposure (beam director)

Deviate mandible, salivary glands and tongue from source of

radiation (in treatment of the lesions on anterior mandible -

anterior floor of mouth - anterior hard palate).

Construction:

Edentulous: sheet of wax or tin foil applied to cone of radiation unit, cone

attached to upper and lower denture base of one piece gunning splint while mouth

is opened, if dorsum of tongue is elevated above cane wax extension used to

deviate tongue.

Radiation

Mostafa Fayad

Dentulous patient: cone attached with self cure to maxillary and mandibular

occlusal index.

c) Displacement (positional) stent:

Function:

Recontour or reposition tissues (in or out of) radiation field for exposure or

protection ex: tongue.

Deviate tongue toward radiation source (extraoral) and avoid radiation of salivary

gland which causes xerostomia.

Construction:

Radiation

Mostafa Fayad

Dentulous patient:

2 sheets of base plate wax extended in flat plane to 2nd molar area, depress base of tongue

to lingual border of the mandible, prevent tongue from extend above occlusal plane, hole

is made in anterior portion, in which tongue tip rest reproducible position.

Edentulous patient:

Impression jaw relation: interim record (conventional steps of complete denture

until JR record) casts mounted on articulator, 2sheets of base plate wax

attached to mandibular record base to from stent that will depress tongue.

Also acrylic duplicate of old denture may be used and lined with tissue

conditioner.

Direct tech: Sheet of softened base plate wax formed in patient mouth to desired

position over existing dentition invested, processed in acrylic resin.

d) Intra oral radiation protective stent:

Function: Remove structures from radiation field.

Types:

Radiation

Mostafa Fayad

A. Stent used to protect the maxilla, parotid gland (to avoid Xerostomia): by

maximum opening of the mandible (large one piece stent), if it is difficult to insert

especially with trismus use 2 piece stent.

B. Stent used to protect the tongue (tongue protector): in treatment of buccal mucosa,

posterolateral border of tongue, alveolar ridge protect tongue and opposite side

of mandible.

Construction:

Patient is asked to bite on soft compound ball push check, tongue aside (made

during impression of mandible).

Mandibular and maxillary cast mounted on articulator at centric occlusion with

incisal pin opened 2-3mm 3-4 sheets of wax softened, placed between teeth

form occlusal index. Wax strip fit into lingual surface (concavity) created by

compound lingual wax extension is covered to create 1cm concavity then

packed into acrylic resin.

Low fusing metal (lead-cerrobend) is melted and poured in cavity of acrylic resin

prosthesis, covered by acrylic resin or wax to decrease scattered radiation (2-3min

thickness lead if low voltage radiation, 5mm thickness lead if high voltage

radiation used).

If patient is edentulous it is made on duplicate upper, lower denture.

Needle invested in acrylic resin of affected side to irradiate ridge growth.

Radiation

Mostafa Fayad

e) Positioning dosemetric device stent:

Function

Measure exact amount of radiation (of lithium fluoride capsule).

Construction

Capsule wrapped by tin foil for separation. Self cure acryl wrapped around it

(carrier).

Stent is stabilized by maxillary and mandibular record bases or interocclusal wax

waver. Hole placed in one end of stent, orthodontic wire used to push capsule

out of resin.

Acrylic resin carrier attached to stent in appropriate position (made with

compound to detect good position).

f) Stent for recontouring tissue to simplify dosemetery:

This stent used in radiation of skin of upper and lower lip, as in this site

radiation at corner of mouth is less than mid line of lip due to curvature of lip

stent is used to flatten lip, corner of mouth entire lip at the same plane.

Made from modeling plastic, processed to acrylic resin.

Radiation

Mostafa Fayad

g) Positioning radioactive source:

Carry source of radiation near lesion in treatment of lesions of (palate- buccal

mucosa - small superficial lesion at any area of mouth).

Source incorporated in denture base ex: maxillary denture base in treatment

of recurrent carcinoma of posterior wall of maxillary sinus.

h) Positioning radioactive source by after loading:

As positioning radioactive source except radioactive source placed in stent

after stent secured into position, placed in poly ethylene lube.

Radiation

Mostafa Fayad

Used in: accessible superficial area – to avoid exposure of the technician to

radiation-

After treatment source removed, placed, in container.

i) Stent used in direct implantation:

Some lesions as (tongue - anterior floor mouth) treated with direct implantation

of radioactive source in the tumor.

Prosthesis with tissue conditioner is used to secure position of radioactive

source during treatment and to achieve patient comfort.

j) Stent used to prevent tongue and check biting:

Irradiation of tongue and check lesions leads to edema, mucostis, check biting

stent used to displace tongue, checks, placed over teeth as mouth guard or

fluoride carrier.

Radiation

Mostafa Fayad

Trismus

Mostafa Fayad

TRISMUS

Limited mandibular movement

A Maximum mandibular opening may be reduced to 10-15 mm, impairing, speech and deglutition, and limits access for dental treatment.

In the past, this word was often used to describe the effects of tetanus, also called 'lock-jaw'. More recently, the term 'trismus' has been used to describe any restriction to mouth opening, including restrictions caused by trauma, surgery or radiation.

Etiology:

I. Acute factors:

1. Local trauma can occur during an inferior alveolar block injection which can result in muscle inflammation that limits movement and causes pain.

2. Infection of the pterygomandibular space can limit mandibular movement also infection can occur as a sequela to pericoronitis or oral surgery.

3. Psychological and emotional stress.

II. Chronic factors:

1. TMJ dysfunction is the most common chronic cause of trismus.

2. Poor joint architecture and malposition of the disk.

3. Rheumatoid arthritis can also be a cause of TMJ pain and restrict mandibular movement.

4. Pathological processes as osteoma of the mandibular condyle or the zygoma, cysts, and overgrowth of the condyle or coronoid process of the mandible.

5. Intra or extra capsular ankylosis of the TMJ can restrict mandibular motion.

III. Treatment related factors:

1. Radiation therapy may limit mandibular movement if the muscles of mastication or TMJ are included in the treatment fields. It is most noticeable following nasopharyngeal, palatal and nasal sinus tumors.

2. Trismus is caused by surgical resection of the maxilla and mandible.

Trismus

Mostafa Fayad

Factors external to the joint include neoplasms, acute infection, myositis, systemic

diseases (lupus, scleroderma, and others) pseudoankylosis, burn injuries or other

trauma to the musculature surrounding the joint.

Factors internal to the joint include bony ankylosis (bony in growth within the

joint), fibrous ankylosis, arthritis, infections, trauma and (perhaps) micro-trauma that

may include brusixm.

Central Nervous System disorders can also cause limitations to mouth opening.

Tetanus, lesions that affect the trigeminal nerve and drug toxicity may all be suspects

in this condition.

iatrogenic causes, such as third molar extraction (in which the muscles of mastication

may be torn, or the joint hyperextended) hematomas secondary to dental injection and

late effects of intermaxillary fixation after mandibular fracture or other trauma.

Signs of trismus

The most obvious effect of trismus is difficulty in opening the mouth.

A simple test for trismus

Trismus tends to develop slowly. In some patients, it progresses so slowly that they may

not notice it until they can only open their mouth to 20mm or less. Treatment that begins

early in the progression of the condition is likely to be more effective, and easier on the

patient. Because of this, it is important to be proactive in looking for early signs of

trismus.

Mouth opening varies from person to person. It is usually 35-55

millimeters. This distance is usually equal to the width of three

fingers. One simple test is the 'three finger test'. Ask the patient to

insert three fingers into the mouth. If all three fingers fit between the central incisors,

mouth opening is considered functional. If less than three fingers can be inserted,

restriction is likely.

Trismus

Mostafa Fayad

Treatment:

The treatment modalities for trismus or limited mandibular movement include medical, surgical and physical therapy. Each mode may be used alone or in combination with other modes of treatment.

I. Medical treatment:

When infection is the cause of trismus, antibiotics are the treatment of choice. Arthritis, inflammation of the joint can be treated with anti-inflammatory agents which relief pain and result in some improvement in motion. Muscle relaxants may help in acute cases of limited mandibular movement.

II. Surgical Treatment:

Surgery is the treatment of choice for removal of tumour ,cysts or foreign bodies. Surgery may also be indicated in TMJ ankylosis and scleroderma after more conservative therapy has failed.

III. Physical Treatment:

Several methods have been utilized to counteract trismus and increase inter-arch space including exercise and the use of mechanical devices, and aids to improve circulation.

A. Exercise:

Exercise is helpful during radiation therapy, following orthognathic surgery and for scleroderma patients.

These include opening the mouth as wide as possible 20 times at least three to four times per day.

In addition 8 to 10 actively assisted lateral excursions should be done to exercise the pterygoid muscles.

downward pressure on the mandible (8-10 times for 10 second).

For scleroderma patients, manually assisted exercise may also be used.

Trismus

Mostafa Fayad

B. Mechanical devices:

a) Simple devices:

1.Tapered threaded acrylic screw:

A tapered threaded acrylic screw can be used, placed and turned between the teeth to apply an opening force to the mandible.

base plate wax is twisted to form a screw with desired taper, then processed into acrylic resin.

2. Tongue depressors

It can be lubricated with petroleum jelly or glycerin and placed between the arches for one minute to increase opening. Additional depressors can be added one at a time to increase opening.

3. Wooden clothespin

It can be inserted between arches while the patient applies gradual pressure.

4. Flex jaw exercisers

b) Dynamic bite opener (T.M.J. exerciser):

Dynamic bite opener is a modified kingsley splint, which is a combination of maxillary and mandibular stents, with metal rods extending through the commissures of the mouth to permit the use of elastic bands to apply an opening force.

Dynamic bite opener

Trismus

Mostafa Fayad

Construction:

Upper and lower alginate impression is taken in shallow stock tray (as trismus present) after coating the tray with adhesive and the casts are mounted on the articulator.

2 horse shoe shape stainless steel perforated metal plates adapted between occlusal surface of upper and lower teeth to receive acrylic resin maxillary and mandibular occlusal stents (3 mm thickness). The acrylic occlusal stents have mechanical retention from the perforation of the plates. Teeth are lubricated and mix of self cure acrylic resin is applied over the upper and lower plates and the patient bite in centric occlusion to form upper and lower occlusal stents.

2 metal rods are welded to the buccal flange of upper and lower metal plates and extending backward from the commisure of the mouth extra-orally.

Maxillary rod extend back ward in the temporal region where it bend down ward to form a U-shaped crimps in the area of premolars, mandibular rod bent upward to form a U-shaped crimps in reverse direction to the maxillary crimps.

Mandibular rod is parallel to the occlusal plane and maxillary rod is place 10-15 mm buccal to mandibular rod. Elastic bands stretched between upper and lower crimps which exert bilateral positive seating forces on the upper and lower occlusal stents and opening force on the mandible.

If the patient was edentulous, the metal rods attached to the buccal surface of the denture base but detection of the fulcrum exerted by the rods is very important to decrease tipping of the denture base.

Trismus

Mostafa Fayad

The Dynasplint Trismus System

The device is based on low-load, prolonged-duration stretch (LLPS) technology. It is spring loaded for simple, adjustable, reproducible tension at each therapy session. This correct biological stimulus has been proven to permanently lengthen shortened connective tissue.

The device is worn inside the middle of the mouth while the patient is relaxed. Proper placement is essential for the ideal stretch of the masticatory muscles. The patient can hold the device with their hand or attach the counterbalance bars for hands-free therapy.

c) The Inflatable bite opener:

It is consists of maxillary and mandibular stents, an inflatable pediatric blood pressure bag, rubber bulb and tubing.

The stents are inserted and the inflatable bag is placed between the stents. The bag is inflated by squeezing the rubber bulb, forcing the stents apart.

The pressure is maintained for 10 seconds followed by 1 minutes of rest. The procedure is followed for 10 minutes three times a day.

Four basic parts of appliance acrylic maxillary plate, acrylic mandibular plate, inflatable rubber pediatric blood pressure bag, and rubber blood pressure handbulb with lock-nut attachment and connecting tubing.

d) An intraoral prosthesis with interarch spring:

It can be used for dentulous and edentulous patients. The spring clips are attached to mandibular stent and the free end of the clip locks into a latch on the maxillary stent. The springs provide a constant force bilaterally which is controlled by adjusting the size of loop.

Trismus

Mostafa Fayad

Microstomia Orthoses Journal of Prosthodontics 19 (2010) 161–165

It is dynamic opening devices used in treatment of Microstomia which is is defined as an abnormally small oral orifice.

A limited oral opening can be caused by

surgical treatment of orofacial cancers,

head and neck radiation,

reconstructive lip surgery,

burns,

trauma,

microinvasion of muscles of mastication,

temporomandibular joint (TMJ) dysfunction syndrome,

and genetic disorders.

Scleroderma is a connective tissue disease of the skin, joints, and sometimes internal organs. Facial skin and oral mucosa become thin and taut, and wrinkles disappear, resulting in a mask-like appearance and a reduced oral opening.

Immediate Dentures

Mostafa Fayad

Immediate Dentures

An Immediate Denture: is a complete or removable partial denture constructed

before the teeth are extracted and inserted immediately after the extraction of the

natural teeth.

Advantages

1- Preservation of healthy oral environment

Prevent migration and overeruption of remaining natural teeth.

Control alveolar ridge resorption.

Abnormal chewing habits are avoided.

Little or no disturbance of T.M.J.

Prevent the change in the tongue size.

The facial muscles will function at their natural length avoiding the

creasing of the soft tissues of the cheeks resulting, in extreme cases, in

angular cheilitis.

2- Preservation of appearance:

The patient never appears edentulous. maintaining of a pleasing

appearance

Lip and cheek support is maintained.

Unless pre-extraction models are made the selection of the mould and

the arrangement of the upper anterior teeth can be a problem for the

clinician when providing ‘first time’ complete dentures. When

immediate dentures are provided this problem is simplified.

Natural facial expression and appearance is maintained because the

facial muscles are maintained in their correct position and the

appearance of the natural dentition can be copied.

3- Jaw relations are maintained:

The reproduction of the vertical jaw relationship is much easier to

achieve and more likely to be correct. If only two opposing natural teeth

are present they will act as occlusal stops.

Immediate Dentures

Mostafa Fayad

Centric relation is easier to record: When a patient has been rendered

completely edentulous, the edentulous ridges can only be brought

together close enough to masticate food by an extreme protrusion of the

mandible. This is a habit that can be very difficult to break during the

registration of the horizontal jaw relationship. This problem does not

arise during the construction of immediate dentures.

4- Neutral zone maintained:

During a prolonged edentulous period, because of the absence of the

teeth, the relationship of the cheeks , lips and the tongue change .This

results in a change of the denture space or neutral zone, which, in turn,

can create problems in obtaining a stable lower denture.

The immediate replacement of the extracted teeth with a denture

preserves the neutral zone.

Because the artificial teeth are arranged in a similar manner to their

natural predecessors, chewing will be carried out more easily or even

better than after a period of edentulousness without dentures.

5- Minimal speech impairment:

When dentures are first fitted there is often a problem with speech, not

only because of the position of the teeth, but also because of the bulk of

the denture base. This problem is made worse if the patient has been

without teeth for an extended period, which is necessary after total tooth

extraction, to allow the soft tissues to heal and the initial resorption of

the alveolar bone.

When an immediate denture is fitted adaptation is made very much

easier, the musculature does not have to learn new patterns of behaviour

because tooth position and neutral zone is not changed.

6- Minimal loss of masticatory efficiency:

There is minimal loss of masticatory efficiency because at no time is the

patient without teeth.

7. The patient becomes adjusted to the immediate denture more quickly than with

conventional one.

Immediate Dentures

Mostafa Fayad

8. Healing period is faster and less painful.

9. Protection of the tooth sockets

The trauma of eating may cause haemorrhage and infection in unprotected

tooth sockets. When immediate dentures are provided the sockets are

protected and the blood clots stabilized immediately after extraction.

With haemophiliacs and patients with related blood disorders immediate

dentures provide a form of splinting.

10.Prevent interruption of the digestive function, because the artificial teeth are

arranged in a similar manner to their natural predecessors, chewing will be carried out

more easily

Disadvantages of Immediate Dentures:

1) The immediate denture cannot be evaluated until the insertion appointment.

the patient may well be disappointed or even disapprove of the "new" appearance,

as Patients who have history of difficult extraction may require surgical extraction

that could result in much mutilation and destruction of the alveolar bone.

2) When the dentures are fitted large areas of spacing between dentures and tissues

can compromise the fit as well as the patient’s appearance. This can undermine

the confidence of the already apprehensive patient and can only be corrected by the

use of a temporary reline material followed by an early permanent hard reline.

3) Relining or remaking is required during the period of alveolar resorption.

The immediate denture should be relined or remade in six months to a year

following insertion.

4) It can be prone to fracture. If the anterior teeth are gum-fitted and the denture is

‘open faced’ It is more costly.

5) Increase denture maintenance and patient visits.

6) Increase patient discomfort by combination of post extraction pain and denture-

related trauma.

Immediate Dentures

Mostafa Fayad

Indication

Patient is in good general health

Patient is co-operative

Patient can understand scope, demands and limitations attached to this

treatment option

Patient cannot go without teeth during the healing period

(aesthetic/psychosocial issues)

Patient can afford time and extra cost involved with this procedure.

Contraindications for immediate dentures

1) Previous history of difficult extraction.

The extraction of the teeth must be a traumatic.

A radiograph revealing dense bone, long or irregularly shaped roots or

hypercementosis should warn of possible problems.

The presences of un-erupted teeth or cysts are a positive contra-

indication.

2) Patients who present with gross oral sepsis

If sepsis follows tooth extraction the patient may well refuse to

wear the denture due to pain. With these patients it is

advisable to construct complete dentures only after an

edentulous period when all inflammation has fully resolved.

The success of an immediate denture depends on it being worn continuously for some

days after the extractions so that the healing tissues and blood clots adapt to the shape

of the fit surface of the denture.

Post operative oral and denture hygiene are therefore very important.

3) Patients with neglected oral hygiene.

4) Non co-operative Patients with regard to oral or denture hygiene.

5) Mentally impaired Patients, or the indifferent and unreliable patients.

6) Severe uncontrolled epileptics.

7) Radiation therapy, soft tissue infection, ulcerative gingivitis, sinus infection and

candidiasis are contra indications until resolved.

Immediate Dentures

Mostafa Fayad

8) Aged or medically compromised patients who cannot tolerate multiple

extractions.

Systemic medical conditions such as diabetes, haemophilia, and cardiac disease are

not contra-indications for the provision of immediate dentures if carried out with l

co-operation and approval of patient’s Consultant or General Medical Practitioner.

Treatment Planning For Immediate Dentures

The patient’s medical and dental history should be reviewed.

A clinical examination of hard and soft tissues is performed, with a full- mouth

radiographs and mounted diagnostic casts.

A thorough scaling of the teeth should be carried out before the extractions. This

is necessary to reduce the possibility of calculus being dislodged into the socket

during extraction causing sepsis and delayed healing.

The dentist should discuss the following with the patient::

Limitations of service must be carefully explained.

Notify patient of possible difficulties involved with procedure.

Clinician must understand the patient’s needs.

Immediate dentures don’t fit as well as complete dentures.

They may need temporary linings with tissue conditioners requiring the use of

denture adhesives.

They will cause discomfort (pain of extraction as well as sore spots).

Patient will experience initial difficulty speaking and eating.

Aesthetics may be unpredictable (no trial try-in).

Other unpredictable denture factors such as the gagging tendency, increased

salivation, different chewing sounds and facial contour.

Immediate dentures must be worn for the first 24 hours without removal. If they

are removed, they may not be able to be reinserted for 3 to 4 days.

Because supporting tissue changes are unpredictable, immediate dentures may

loosen up during the first 1 to 2 months.

The patient is responsible for all fees involved in refitting or relining the dentures.

Immediate Dentures

Mostafa Fayad

Types of Immediate Denture

I. According to the stages of teeth extraction it’s classified into:

There are two main methods with regards to the use of immediate dentures in the

ultimate treatment for the patient.

A. Interim (Transitional/ TID) One stage technique

Complete clearance :All the remaining teeth are extracted and the denture

fitted at one session. Advantage to some patients, particularly the

dentalphobic, there is just one surgical, anesthetic and prosthetic procedure.

Probably best done under general anesthesia.

Once the immediate denture is inserted and healing of the extraction socket

is complete, a new complete denture is fabricated.

Retention and stability can be improved by subsequent relines due to initial

rapid resorption of the alveolus post extraction.

Advantages

Vertical dimension preserved as extraction of posterior teeth occurs at the

surgical appointment of the insert.

Indicated when multiple anterior and posterior teeth remain and patient

cannot go without posterior teeth to allow the bone to heal.

Disadvantages,

o Usually very rapid resorption of all alveolar bone resulting in

dentures becoming ill fitting very rapidly.

o If a large number of teeth are involved some practitioners are

reluctant to fit complete immediate dentures questioning the

ethics of such “blood-letting” surgery.

Immediate Dentures

Mostafa Fayad

B. Conventional (Classic/CID) Two-stage extraction technique

There are two versions of this technique:

a- All of the posterior teeth are extracted, preferably retaining the first premolars.

Two extraction visits required

Remove all posterior teeth about 3 months before making immediate denture

Allows for posterior segment to heal and stabilize

Maintains anterior teeth for appearance, some function

Immediate denture inserted at the second surgical appointment.

Once this immediate denture is inserted and healing of the extraction socket is

complete, the denture is refitted or relined for long-term use.

Advantages

Good retention and stability than transitional immediate denture.

The immediate dentures will be better supported because initial

posterior bone resorption has taken place.

The possible disadvantages of this technique are:

If there is gross periodontal disease of the anterior teeth then during the

posterior healing period periodontal abscesses may form and there may

be movement of the teeth.

There is also the possibility that the patient will develop a habitual

mandibular posture in order to masticate the food. This may create

problems during the CJR stage as discussed under advantages to the

clinician.

b- Interim partial denture construction : A modification of the previous technique

is to make an immediate partial denture to the stabilized bony base. After the patient

has learnt to control it the remaining anterior teeth are added as immediate additions.

Advantage:

1-It prepares the patient for complete dentures by first learning how to control

the partial denture.

2-The denture provides posterior support reducing the possibility of the

development of a habitual posturing of the mandible.

Immediate Dentures

Mostafa Fayad

Immediate Dentures

Mostafa Fayad

II. According to Surgical Procedure it’s classified into

A. Immediate Denture without alveoloplasty

Extraction of anterior teeth with no Surgery

Teeth are simply extracted with no surgery performed, the denture is

constructed either with or without labial flanges

B. Immediate Denture with alveoloplasty

Teeth are extracted and followed by a surgical contouring of the alveolar

ridge. Especially patients who has maxillary protrusion and to eliminate

undercuts.

III. According to presence or absence of labial flange

A-The flanged denture

The flange in the anterior region may be either complete or part. The flanged denture

may be either without alveoloplasty or with alveoloplasty.

a) The flanged denture without alveoloplasty

The complete flange

The pressure of a complete flange gives better retention and

protection to the sockets and thus assists more rapid healing.

The part flange:

It is indicated when the undercuts are greater than 2 mm and

in particular when they are diametrically opposed by

undercuts in the posterior region.

The part flange is extended just beyond the maximum contour

of the alveolar process, to a point where the undercut engaged

can be accepted by compression of the overlaying soft tissues,

this type of flange gives some retention to the denture and

avoids the gap between a complete flange and the tissue which

is inevitable where a large bony undercut exists.

Immediate Dentures

Mostafa Fayad

b) The flanged denture with alveoloplasty

There is a small proportion of cases where reshaping of the alveolar

process is indicated. Where there is marked protrusion of the upper

alveolar process and when the patient has a short upper lip, both

appearance and denture function can be improved by alveoloplasty.

Alveoloplasty may be performed by either septal or radial alveolectomy..

B-The open face denture

In this type, the artificial teeth are set (either in or close to the sockets of

their natural predecessors) and labial flange isn’t made.

The open face immediate denture is only indicated in the upper jaw

when sufficient retention can be obtained from the rest of the denture

bearing area.

It may be

Socketted immediate denture

gum fitted immediate denture

Immediate Dentures

Mostafa Fayad

Immediate Dentures

Mostafa Fayad

Clinical Procedures for “CICD” Construction:

1- Examination and Mouth Preparation:

Proper intra and extra oral examination should be carried out.

Good scaling to remove plaque� to obtain accurate impressions and reduce

post-operative edema. Impressions and

Inter-occlusal records are made to obtain mounted diagnostic casts as a

diagnosis, Treatment planning and reference.

2- Posterior Teeth Extraction:

While leaving bilateral centric Stops (bilateral opposing premolars or molars as

guide to jaw relationship). Then 6 weeks of healing than next appointment.

An alternative is to make an immediate partial denture replacing all of the

posterior teeth and inserted immediately after posterior teeth extraction.

3- Preliminary Impressions:

The removal of the teeth should be 4 to 6 weeks prior to preliminary

impression.

Using a proper stock tray and alginate impression to make a study cast. Then a

special tray is constructed.

If the teeth are very mobile, the undercuts and interproximal areas should be

blocked out with soft wax and lightly coating the teeth with petrolatum, to avoid

extracting the teeth with the impression.

4- Final Impressions: either by:

a- Single Final Impression Procedure:

Alginate impression in a boarder molded, perforated acrylic special tray.

b- Two Stage Final Impression Procedure “sectional Impression”:

Used in case of deep anterior undercuts. The impression is first made for

the posterior edentulous using Zinc Oxide and eugenol in an acrylic resin

Immediate Dentures

Mostafa Fayad

tray confined to the posterior only extending only till the positive stop on

the lingual side of the anterior teeth.

Then another impression using alginate on a perforated stock tray is used

while the first impression is still in place, they are removed together as

one.

Campagna technique describes when posterior teeth have been extracted, a custom

tray is border molded with impression compound and a rubber base impression

material impression is taken of the anterior vestibule and edentulous area, reinserted,

and then captured in an alginate wash impression.

Light-bodied rubber is the material of choice for the final impression. In sever

mobile teeth alginate impression is the material of choice due to low tear strength

which allow easier removal of impression.

5- Jaw relation registration and posterior teeth try-in:

The final impression is boxed poured master Cast. Then well adopted occlusion

blocks are made and placed on it,

The lower teeth can help guide its occlusal plane height. The vertical stops can

preserve the vertical dimension. Also the centric occluding relation is recorded.

Teeth selection: is carried out in relation to the remaining teeth.

Arrangement of Posterior teeth: The posterior teeth are arranged on the

recording base. The teeth are set so as to provide multiple bilateral posterior

contacts in centric relation, with bilateral balanced occlusion.

The partial denture is tried in the patient’s mouth to ensure correct Centric

occluding relation.

Then one of two treatment plane is chosen

o 1st technique: The transitional partial denture is finished and

polished. The denture is delivered to the patient. The patient is

dismissed for a period of a few weeks to become accustomed to the

Immediate Dentures

Mostafa Fayad

new dentures, and then cast modifications and the immediate

additions of the remaining teeth are carried out.

One advantage of this method is that it prepares the patient for complete dentures by

first learning how to control the partial denture. Another advantage is the denture

provides posterior support reducing the possibility of the development of an habitual

posturing of the mandible.

o An alternative technique: is to make cast modification and an

immediate addition of the remaining teeth are carried out to trial

denture base and an immediate complete denture is inserted

immediately after anterior teeth extraction. No transitional partial

denture is delivered to the patient

6- Modification of the Master Cast:

Mark the upper and lower casts in pencil to produce

guide lines:

Draw a line around each tooth at the level of the

gingival margin

Draw a line on the long axis of the tooth

Measure the length of the teeth with dividers and scribe these lines on the

cast

Removal of the tooth can be described as shown in the diagram (flanged

denture not socket-fit):

The usual method of gingival trimming is as follows

Cut off the plaster level with the gingival margin.

Hollow out the root to a depth of 2-3 mm.

Trim and round off the gingival margins to the above level.

Immediate Dentures

Mostafa Fayad

The mast cast is modified by

Removing all the stone anterior teeth, The stone teeth are cut from the

model and replaced by artificial teeth. This is best achieved by removing

and replacing one tooth at a time '' so that the form of the arch and the

position of each individual tooth can be more easily copied if desired''.

Contouring the residual ridge depending on the treatment plan

previously made during examination.

The cast is made to give the same shape to the post surgical contour previously

planned and that in which it will be carried out in the surgical appointment.

If alveoloplasty is planned to be done with exaction of anterior teeth :

The master cast is modified by cutting off the teeth and trimming of the

labial alveolar portion to eliminate the undercut or the protruded area.

a clear acrylic resin template was made previously on a duplicate

modified cast to determine the amount of bone to be contoured During

surgery

If no alveoloplasty is planned to be done with exaction of anterior teeth :

With Socketted immediate denture: The anterior teeth are extended a

few millimeters into the labial aspect of the sockets.

With Flanged Immediate Denture: removing all the stone anterior

teeth with no extension into the socket.

Immediate Dentures

Mostafa Fayad

Root sockets are prepared in the stone model into which the necks of artificial teeth are

fitted. So that when the complete denture is inserted in the mouth after the extraction

of the natural teeth, these necks just enter the natural socket.

The direction of the socket should follow the long axis of the tooth.

1- The socket depth never more than 5 mm.

2- Don’t carry the socket too far towards the palatal side.

7- Surgical Procedure and Extraction of Anterior teeth:

o Extraction of anterior teeth with no surgery: All remaining teeth are

extracted as planned before the cast modifications.

o Exaction of anterior teeth with alveoloplasty: During surgery the amount

of bone to be contoured is determined and guided by a clear acrylic resin

template previously made.

8- Denture Construction:

The trial denture base is extended to the anterior region and the selected

artificial teeth are placed in position with wax, flasked , processed ,

deflasked , finished , polished and ready for insertion.

8- Denture Insertion:

The use of a pressure paste to identify any pressure points on the fitting surface

then they are eliminated.

The patient should wear it for 24 hours continuously � it shouldn’t be removed

as the tissue will swell if removed making it impossible to reseat.

9- Post-Insertion care:

Scheduled visits should be made: the following day, 48, and 72 hours later.

The Patient should be recalled every 3 months to evaluate and check the

denture’s: fit, retention and stability.

Immediate Dentures

Mostafa Fayad

In most cases of CICD rebasing will be required within 10-14 months after

insertion.

If the treatment plan involves making the upper and lower dentures separately, then the

lower denture should always be made first. In this way the height of the lower anterior

teeth and their relationship to the upper anteriors can be optimized.

Anterior teeth Selection:

The existing dentition is utilized in selecting a shade and mold of artificial teeth

, or the natural teeth are duplicated as the following:-

1- An alginate impression for the upper and lower teeth is made.

2- Molten wax is poured into the alginate impressions. The teeth wax pattern is

removed after cooling.

3- The wax patterns of the upper and lower teeth are flasked. The wax is

eliminated , and the artificial teeth are packed by the autopolymerizing acrylic

resin of the same color of natural teeth. And then the teeth are processed

4- The teeth are removed from the mold as a block of teeth. a saw or disk is used

to separate them at the incisal edge and buccal surface while keeping the them

in contact at the cingulum area, Teeth are polished. attached to the modified

master cast (instead of the readymade artificial teeth)

Relation of the artificial teeth to the soft tissues:-

(1) Gum fitted, this is the first preference for this type of

denture,

(2) Socketed. Only used when the teeth have been extracted

because of periodontal disease resulting in alveolar bone

loss.

(3) A fully flanged denture.

(4) A part flanged denture (called “half flanged denture”).

Whenever possible a flanged denture should always be constructed.

Immediate Dentures

Mostafa Fayad

It is less destructive to the soft tissues.

The retention is greatly improved compared with an open faced one.

The appearance is much more acceptable.

An open-faced denture should very rarely, if ever, be used in the lower arch.

If there are gross bony undercuts present then it may be impossible to

provide a flanged denture without surgical reduction of the bone, but the long

term effects of alveolectomy should always be considered before resorting to

surgery as noted earlier when referring to alveolotomy.

The problem areas are commonly in the upper anterior region, particularly with

patients whose incisors were proclined that is Class II Div.1. malocclusion, and in the

tuberosity region.

Open face design is only suitable when the teeth have pocket depths of less than 3

mm. When pocketing is greater than 3 mm., a flange should always be used.

the anterior teeth are set up, prior to finishing, according to the choices referred to

above having been decided they can be gum fitted, that is, .the necks of the teeth

contoured to the alveolar ridge without intrusion into the future sockets or socketed

when the necks of the teeth are inserted into a depression carved out from the model to

represent the sockets.

The former method, gum fitted, is preferred. If the teeth are socketed the long-term

consequence could be the production of a scalloped, that is, undulating ridge.

Immediate complete denture without alveoloplasty

Replacement of the natural teeth by artificial teeth:

When it is decided to place the anterior teeth in their original position, the

following steps should be done:

Upper and lower impressions, with the dentures in position, are made and

poured with dental stone.

Cast modification:

One stone tooth by one is removed and replaced by artificial tooth in

the same position; the position of each individual tooth can be more

easily copied.

Immediate Dentures

Mostafa Fayad

Root sockets are prepared in the stone models into which necks of the

artificial teeth are fitted.

o The labial root portion of the teeth is excavated to

approximately I mm on the labial side and flash with the

gingival margin on the lingual or palatal side. The depth of the

socket should never exceed 5 mm (socketted denture)

The denture is waxed-up and processed in the usual manner.

After tooth extraction, the denture is checked for any pressure area by

pressure indicating paste. Then the denture is lined by tissue conditioning

material and inserted into the patient’s mouth.

Advantages of root socketing

It allows for initial alveolar resorption (no unpleasant gap appears between the

neck of tooth and alveolar ridges)

It provide anterior seal which assists retention of denture.

Gives natural appearance of the denture and protrusion of lip is avoided.

Difficulties in estimating the correct amount of trimming of the cast is avoided.

Disadvantages

1- Absence of labial flange leads to decrease in retension and atability

2- Labial flange help healing and conservation of ridge.

3- Not suitable for mouth need bone trimming as superior protrusioin.

The lower denture

Don’t make socketing the anterior teeth because the stability of the lower denture is

much less than the upper, and the movement of the denture during mastication cause

pain as the artificial roots move in the sockets.

Greater stability will be obtaine and the pain is reduced if the lower denture is made

with normal labial flange.

Immediate Dentures

Mostafa Fayad

The Clinical Techniques

The depths of the periodontal pockets are assessed and recorded

The clinical procedures involved in the construction of immediate dentures follow

very closely those used for the construction of partial dentures.

Primary impressions are taken for study casts and the construction of special trays.

Secondary impressions are taken in the special trays for an accurate recording of

the denture bearing areas and the production of the working casts on which the

dentures are made.

Record rims made on the working casts, are used to register the centric occlusion at

the correct occlusal vertical dimension.

A face-bow record is taken at this appointment.

The working casts are mounted on an articulator (preferably a semi-adjustable one)

with the face-bow recording and using the split cast technique.

The wax trial denture, set up as a partial denture, is tried in the mouth and the

occlusion, vertical relationship and tooth shade and mould checked.

A post-dam is cut on the cast and an ante-dam just behind the teeth to be replaced.

The articulated casts and wax trials are returned to the laboratory for conversion to

immediate dentures, in wax, before processing

The working casts should be duplicated before modification.

The Laboratory Techniques

The teeth on the casts are cut off one by one to the height of the gingival

margins then, according to the type of denture decided upon, the cast is trimmed and

the artificial teeth are ground to fit the labial aspect of the prepared sockets.

Ideally the trimming of the casts should be done by the clinician as he will be

aware of the state of the tissues, the extent of damage by periodontally involved teeth

for example.

When the artificial teeth have replaced all the plaster teeth, the denture base is

laid down in wax and the wax denture flasked, packed and finished in acrylic resin. If

the split cast technique is used before flasking, the occlusion can be balanced to

eradicate any errors, which may have arisen during the processing. Less time will be

required when balancing the occlusion at the fit stage in the surgery.

Immediate Dentures

Mostafa Fayad

Fitting the Dentures in the Surgery.

Clear instructions should be given to the patient. This can take the form of verbal

instructions or better still, in a written form.

The patient should be instructed that for the next 24 hours the dentures should only

be removed briefly in order to clean them after meals then re-inserted as quickly as

possible.

They should be worn at night for at least five days after the fitting.

An appointment should be given for the following day for the first review to

examine the sockets and make any necessary adjustments to the dentures.

A further review appointment should be made for examination after one week.

Immediate complete denture with alveoloplasty

Indications:

A prominent pre-maxilla as in Angle Class II, division 1.

Patients who have a short and thin upper lip and a prominent labial alveolar ridge.

A very close bite anteriorly.

In order to provide better retention and stability of the denture.

Technique of construction :

1- Upper and lower alginate impression with the dentures in position are made and

poured with dental stone.

2- The incisors and canine teeth are cut from the model and the stone representing the

alveolar ridge is trimmed to the desired shape.

3- The trimmed cast is duplicated, and a transparent acrylic resin template of 2 mm

thickness is fabricated on the duplicate cast.

4- Setting-up of anterior teeth is carried-out. The denture is waxed-up with labial

flange in position (flanged denture). Then the denture is processed.

5- Mucoperiosteal flap is reflected and all the remaining teeth are extracted.

Immediate Dentures

Mostafa Fayad

6- The bone and the soft tissue are trimmed until the template is securely seated

against the palate or on the mandibular residual ridge without any spots of pressure.

Then the wound is sutured.

7- The dentures are then placed in the mouth and the patient is asked to close for the

first check of occlusion. Pressure indicating paste is used to check for pressure

area, which is removed if present. The denture is relined by tissue conditioning

material and delivered to the patient.

8- Sutures are removed after 7 days. The occlusal correction should be postponed for

as long as 2 weeks.

Immediate denture without prior extraction of the posterior

teeth:

Indication

1- When the anterior teeth are causing pain or excessively loose.

2- If the patient wishes to shorten the number of visits for extraction.

Technique:

This method is not suitable for general practice and should only be employed if the

patient can be treated in a hospital or nursing home.

Alginate impression are taken for both jaws.

The models cast from this impression are mounted on an articulator by means of

interocclusal wax record.

Duplicates of these models are made for reference when setting the teeth.

Immediate Dentures

Mostafa Fayad

The stone teeth removed from the cast and replaced by acrylic teeth. This is best

achieved by removing and replacing one tooth at a time until the all teeth are replaced.

The denture is then processed and finished as usual. The denture is cooled sterilized

and inserted into the mouth immediately after extraction. The post operative case and

instruction is as mensioned before.

The complete immediate over denture:

Complete immediate overdenture were evaluated by Jonkman et al 1995, they found

no differences in comfort, chewing ability, aesthetics and general satisfaction between

patients wearing immediate complete dentures and patients wearing immediate

overdentures.

Delayed immediate denture

This denture is inserted within few days after extraction of the teeth

Clinical and technical procedures:

All the posterior teeth should be removed 4 to 6 weeks prior to impression making.

Alginate impression is performed for both jaws, and stone cast are poured. Jaw

relatioship are recorded in the usual manners of partially edentulous cases and the

models are mounted on the articulator. The posterior teeth are set up and the waxed

partial dentures tried in the patient mouth. The trial denture are returned to the

articulator, the front stone teeth are cut from the models and the gingival margins are

rounded. The base plate is extended to cover the ridge anteriorly and the artificial

anterior teeth are set up. Now we have complete waxed dentures.

The anterior teeth are extracted and the alveolar plate are squeezed. The patient is

asked to bite on cotton rolls for few minutes to stop the oozing blood. The waxed up

complete dentures are tried in the patient’s mouth and necessary adjustements may be

done. Zinc oxide eugenol impressions are made after extraction using the waxed up

dentures as trays.

Immediate Dentures

Mostafa Fayad

The impressions are poured, flasking, packing, finishing and polishing are carried out

in the usual manner.

Advantages of this technique

1- It has better initial fit and adaptation as the impression is taken after extraction of the

teeth.

2- The waxed up complete denture is tried in the patient mouth .

3- It gives a longer period of satisfactory service comparing to the conventional

immediate denture.

Immediate partial dentures

These dentures may be construct to replace missing anterior or posterior teeth. due to

the stability of the partial denture which has natural teeth to support it, the results are

very satisfactory.

Permanent immediate partial dentures.

In these types the try-in of the metal framework is difficult and if the framework fails

to seat at the time at the time of insertion the patient will be left edentulous until

reconstruction of the denture.

There are two techniques that will permit try-in of the metal framework before

completing the prosthesis. The first technique used wrought wire projection to act as

the retention minor connector for the acrylic denture base. During the framework try-

in these wire can be bent backward so it will not interfere with the teeth that will be

extracted. After the try-in the wires may be adjusted to the cast for positioning of the

artificial teeth and waxing the denture base.

In the second technique the master cast is relieved, blocked out and duplicated in

refractory material. The teeth are to be extracted and replaced by the partial denture

are cut from both the duplicate refractory cast and the master cast. In the refractory

cast the framework is waxed with separate acrylic resin retention areas, then invested

and casted (Fig. 13-8). The framework is now tried in and fitted to the abutment teeth.

Immediate Dentures

Mostafa Fayad

The framework is then placed on the master cast and the acrylic resin retention minor

connectors placed in position and soldered to the framework (Fig.13-9). Space must be

provided between the minor connectors and the cast for the acrylic resin denture base.

Denture teeth are set and denture base is waxed to proper contour (Fig 13-10).

In both technique relining the denture base will be required as healing and resorption

of the edentulous areas take place.

Metal framework with separate acrylic resin retention minor connector.

Teeth to be extracted and replaced are cut from the cast and acrylic resin retention is

soldered to framework.

Immediate Dentures

Mostafa Fayad

Temporary immediate partial dentures

This type is constructed from acrylic resin and can be used successfully for a long time

to allow for complete healing before construction of the definitive prosthesis. It has the

advantage that changes in the denture base or teeth can be made easily. Impression

mounting the casts, and replacement of the teeth are the same as the definitive one but

the denture are constructed from acrylic resin.

relining of denture base will be necessary during the healing period.

Post operative instructions

Clear and specific instructions be given to the patient

Advise patient not to remove the dentures to ensure minimal disturbance of blood

clot.

No vigorous mouth washing

Reduce possibility of post-extraction hemorrhage to avoid undue exercise, alcohol,

hot food and drink

Analgesic tablets given to reduce postoperative pain

Appointment should be arranged for next day.

Immediate Dentures

Mostafa Fayad

Dietary advice:

Included upon the written instructions are instructions and advice about the diets that

they may expect to be able to manage with their immediate dentures.

It should be expected within the first 24 hours that they can manage only semi-

fluid foods.

Within the first week the patient should be encouraged to extend the range of

goods eaten, gradually eating harder foods.

After the first month, patient may eat a normal diet.

First 24 Hours:

Wear the immediate dentures continuously day and night and not to remove them.

Hot drinks avoided

Analgesic should be given

Dietary advice

Examination after 24Hrs

Surgical area irrigated with warm saline

Removal of denture with no alveoloplasty there should be firm healthy clots in the

sockets with no sign of continuing hemorrhage. Any oozing from sockets indicates

delayed clot formation due to trauma from denture or systemic causes

If alveoloplasty has been performed, sutured mucosal margins should be in close

contact. Rebasing is necessary if changes in shape of the ridge are greater then

planned on the cast.

Assess areas of inflammation, adjustment of fitting surface prevents progression to

ulceration.

Must inform patient to use immediate dentures for mastication; moderate

mastication increases blood supply and assists rapid healing.

Saline solution causes dehydration and shrinkage of the blood clot.

If surgical area is clean and adjustments are minimal, patient needn’t be seen for

another 7 days. If friable blood clot or there is considerable denture adjustments

necessary, it is advisable to see patient 3 days after surgery

Immediate Dentures

Mostafa Fayad

One week:

Any sutures are removed

occlusion checked and corrected if necessary

continue wearing continuously and to remove the denture three times a day as he

did during the first week to clean it and carry out a similar routine of oral hygiene.

If healing uneventful, next visit may be a month after extraction

If there are changes to the alveolar ridge, possible requirement to rebase; patient

must understand the need for regular servicing of dentures.

One month:

- oral tissues examined

- occlusal imperfections and tissue damage should be noted

- advise patient to leave the dentures out at night

- chemically cleaning may be advisable

Three months:

- resorption of the alveolar bone should have occurred and the tissues should of

healed completely.

- Relining of the denture may be required.

Airway sleep disorders

Mostafa Fayad

Removable prostheses for airway sleeping disorders

Introduction:

Upper airway sleep disorders (UASD) are becoming commonly recognized by the

medical and dental communities, and patients are now being referred to dentists for

treatment of these conditions using removable oral devices.

Snoring is the mild form of these disorders, obstructive sleep apnea (OSA) is the

severe form, and upper airway resistance syndrome (UARS) falls some where

between the two.

Anatomy:

In the normal anatomy, the upper airway is a soft tissue tube,

maintained by muscle activity extending from the oral and nasal cavities to

the bronchial tubes.

The activity and timing of the tensor veli, elevator veli palatine,

genioglossus, and geniohyoid muscles maintain the position of the soft

palate, uvula, tongue, and hyoid bone in a position away from the posterior

wall of the pharynx.

The airway patent of snoring patients is partially obstructed. This

obstruction is very often caused by the tongue and /or hyoid bone and

overlying soft tissues dropping back toward the posterior wall of the pharynx. In attempting to

get sufficient oxygen to the lungs, there is an increase in velocity of air passing through the

reduced airway space. This increase in velocity may cause flabby tissue, often the soft palate and

/or uvula, to vibrate. This vibration is the sound of snoring.

Treatment Options

Once diagnosed with a UASD, the physician has five basic treatment options:

behavioral modification,

surgery,

continuous positive air pressure (CPAP),

oral devices,

Medication.


Mostafa Fayad

upper airway muscle tone: mild OSA – avoid alcohol and sedatives

upper airway lumen size:

o Mild to moderate OSA –weight reduction, avoid supine position and

use oral prosthesis to keep airway patent

o Severe OSA: Uvulopalatopharyngoplasty

upper airway subathmospheric pressure:

o 1.mild to moderate OSA – improve nasal patency;

o 2.severe OSA – nasal CPAP

Bypass occlusion: severe OSA - tracheotomy


Mostafa Fayad

Oral Devices

Types:

Oral devices are of two basic configurations,

Mandibular advancement device (MAD).

Tongue retaining device (TRD)

The TRD is laboratory fabricated; MADs may be stock devices or laboratory fabricated.

Mode of action:

Oral devices generally work by directly or indirectly preventing the tongue form

approaching the posterior wall of the pharynx.

The TRDs work through the use of a hollow bulb and sufficient vacuum to hold the

tongue forward.

The MADs work indirectly by holding the mandible and hence the tongue forward. These

devices also aid in preventing the hyoid bone form dropping posteriorly and its overlying

tissues from impinging on the upper airway.

All dental devices are obviously intraoral and therefore require a certain amount of space and

movement of the mandible or tongue.

Tongue size and the amount of space between the soft plate and tongue are objective evaluations

that may help identify a compromised upper airway or be useful in determining the type of

device most suitable for a patient.


Mostafa Fayad


Mostafa Fayad

A] Mandibular advancement devices

MADs are either adjustable or single – position devices.

Single-position MADs depend upon the clinician properly determining the desired protrusive

position that will eliminate the snoring and/or OSA.

Single-Position Stock Devices [single-piece single-position stock device].

These devices are generally fabricated from two rigid-plastic sheets in the shape

of impression trays joined into a single unit.

The trays fit over both the maxillary and mandibular teeth

simultaneously and receive retention from a thermoplastic

fill material.

The mandibular side of the device has a vertical arm

extending lingually below the plane of occlusion and behind the mandibular

anterior teeth.

Retention is not required on the mandibular arch because the lingual surfaces of

the mandibular anterior teeth are in direct contact with this lingual projection.

This flange will prevent the mandibular arch form moving posterior during sleep.

An interocclusal record is often made at approximately 70% to 75% of the

maximum protrusive movement.

A tongue blade is placed between the maxillary and mandibular incisors

with the patient in the normal retruded occlusal position.

A small mark is made on both the top and bottom of the tongue blade in

the midline and against the maxillary and mandibular incisors. The patient

is than asked to thrust the mandible as far forward as possible in a

protrusive movement with minimal lateral deviation, and a second mark is

made.

The distance between the two marks, multiplied by 0.7 is approximately

70% of the patient’s maximum protrusive movement.

An interocclusal record is made at this point. The tongue blade is also used

to determine the maximum vertical opening of the mandible.


Mostafa Fayad

Adjustable Stock MADs

These devices are generally shaped like plastic impression

trays. The trays are filled with thermoplastic material for fitting

to the patient with some mechanism for adjusting the mandible

in a protrusive and retrusive direction. e.g Stock two piece

adjustable device with a screw mechanism. A screw mechanism for positioning the mandible is commonly used. A potential

disadvantage of this device is that the patient must be very careful when adjusting the

screws.

The two-piece adjustable devices do not require as much interocclusal space as one piece

devices. The thermoplastic material allows multiple adjustments as necessary, and the

adjustability allows the mandible to be protruded the minimum distance necessary to

achieve satisfactory results.

Adjusting the screw mechanism either moves the mandible in an anterior direction and

indirectly moves the tongue away form the posterior wall of the pharynx or the mandible

is allowed to drop more posteriorly, reducing stresses on the TMJ.

The interocclusal records are made at approximately 50% of maximum protrusion and

with at least 5 mm of clearance between the anterior teeth.

If the device reduces snoring to an acceptable level or eliminates it following insertion and no

TMJ or tooth discomfort is reported, adjustment is not necessary and the device can be worn

with the mandible in its initial position. However, if the snoring level is not acceptable, then the

mandible is slowly protruded 0.25 mm per night for no longer than 2 weeks, at which time the

patient is re-evaluated. This protrusion is resumed and continued until the desired snoring results

are achieved or TMJ discomfort begins.


Mostafa Fayad

Tongue Retaining Device (TRD)

The TRD (e,g. Flexible tongue retaining device) is an

excellent device for edentulous patients or those who suffer

form TMJ sensitivity.

This is a one-piece device made of a non rigid vinyl material

without thermoplastic material to adapt to the teeth.

The effectiveness of these devices depends upon holding the tongue forward in a hollow

bulb away from the posterior wall of the pharynx.

Fabrication of this device requires a kit containing two hollow bulb templates. The

templates are basically hollow bulb devices on top of the tray of the device.

The templates is used to select the proper bulb size necessary to create a vacuum to

hold the tongue, to position the bulb to achieve the desired tongue protrusion, and as

tray to hold interocclusal recording material.

Once the proper bulb size is selected and the tongue is well retained in the hollow

bulb by the vacuum, the patient is asked to protrude the tongue the maximum

comfortable distance possible, and the incisors are closed onto the anterior part of the

template.

Air is squeezed out other bulb to achieve the vacuum, necessary to retain the tongue

in the hollow bulb.

Poly vinyl silaxance bite-recording material is placed on the sides of the template.

The template with recording material and diagnostic casts is used to fabricate the

actual TRD for the patient.

Patient instructions:

When initially inserting the device, the patient should be instructed to place the

device over both arches and push the tongue into the hollow bulb.

The patient is instructed to create a vacuum in the oral cavity, the bulb is squeezed

until as much air as possible is removed from the bulb and a significant vacuum is

created, especially around the tongue. The patient is should be instructed to relax the lips and relapse the vacuum around

the maxillary and mandibular arches. The tongue must be well retained within the


Mostafa Fayad

hollow bulb by the vacuum at this point and should be difficult to pull the device

off the tongue. The patient is instructed to protrude the tongue into the hollow bulb and the

vacuum should hold it there for several hours per night a minimum of 6 hours of

sleep with the device inserted should be the goal for the patient.

Total and Partial Glossectomy

Mostafa Fayad

Prosthodontic Rehabilitation Following Total and Partial

Glossectomy

Tongue defects due to tumor removal can result in either total or partial glossectomy.

Effect of glossectomy:

a) Total glossectomy

When near total glossectomy is performed, the normal functions of speech

and swallowing are disrupted.

Role of tongue in speech production

The tongue shapes the oral and pharyngeal cavities for vowel

production. It restricts air flow in the oral cavity to produce

consonants linguovelar, linguopalatal “K”, linguoalveolar “g”,

linguodental “T” “D” and “S” “Z”.

The tongue is the major articulator during the production of all

phonemes, with the exception of the bilabial and labiodental sounds.

Compromise of the tongue secondary to surgical resection, resulting

in altered volume, limited and restricted movement of the tongue.

Tongue segments, or flaps, can have an adverse affect upon the

quality of speech.

Limitation of surgical management

With the development of mycocutaneous flaps and free flaps, there

has been an increased frequency of surgical attempts to rehabilitate

the total glossectomy patient.

The major problems with these flaps are bulk, lack of voluntary

control with limited or no sensation.

When these flaps are used, consideration should be given to limiting bulk,

allowing room for future prosthodontic rehabilitation in the mandibular arch.

An awareness and use of the palatal speech and swallowing prosthesis should


Mostafa Fayad

be stressed to the surgeons to assure them that excessive bulk may actually

hinder future rehabilitation.

b) partial glossectomy

In patients with partial glossectomy defect the status of the remaining

tongue is the most important prosthodontic prognostic indicator.

The motor and/or sensory control of the tongue has been

significantly compromised by the resection; the prosthetic prognosis

becomes extremely guarded.

The mobility and bulk of the tongue is also important. In stabilizing

the mandibular denture during function. Small amount of residual

tongue can move a large bulk of free flap if motor innervations are

intact.

The determination of whether a speech or deglutition aid prosthesis

should be placed in the maxillary or mandibular arch has been based on :

Volume and mobility of residual tongue or reconstructed flaps.

presence and condition of teeth to help stabilize the prosthesis,

mandibular range of motion,

lip and cheek mobility,

tongue sensation and position,

commissure width.

Prosthodontic Treatment of Total Glossectomy

In total glossectomy, the mandibular tongue prosthesis is the treatment of

choice.

However, in a situation involving an edentulous patient and an irradiated, resorbed

mandibular ridge or a patient with a very mutilated dentition, palatal augmentation

prosthesis should be considered.

The major goals in prosthodontic rehabilitation of the total glossectomy

patient without surgical reconstruction are to:


Mostafa Fayad

Reduce the size of the oral cavity, which improves resonance.

Direct the food bolus into the oropharynx with the aid of a trough.

Protect the underlying fragile mucosa if skin flaps were not used.

Develop surface contact with the surrounding structures during

speech and swallowing.

Improve appearance and psychosocial adjustment.

Mandibular Tongue Prosthesis:

One objective for the prosthetic tongue is to increase the speaker’s

potential for shaping the voice tract to achieve closer to normal resonance.

The dome-shaped tongue prosthesis fills the palatal vault, anterior-to-posterior and

laterally, as much as the normal tongue when the mandible and teeth are closed.

It has been suggested that three prosthetic tongues be made: one for

speech one for swallowing, and one for both speech and swallowing.

a) The prosthetic tongue for speech

1- It should have

An anterior elevation to facilitate

articulation of the anterior

linguoalveolar sounds t and d. It should also have a posterior

elevation to aid in the articulation of

the posterior linguopalatal sounds g and k. Both elevations

help to shape the oral cavity, thus improving vowel

production in general.

2- Retention: When the mandibular arch is partially edentulous, the

tongue prosthesis is incorporated into a removable partial

denture. The retentive meshwork of the framework is extended

into the defect to include a major portion of the floor of the

mouth and to provide support for the impression material.


Mostafa Fayad

3- Construction: To construct the prosthetic tongue for speech,

gray stick compound elevations, is luted to the anterior

portion of the framework and the patient is asked to

occlude the teeth.

Compound is then added o the posterior portion of the

framework and the patient is asked again to occlude the

teeth.

Contact with the palate should be evident in both areas of

compound. Both anterior and posterior elevations are

reduced 2 to 3 mm and a layer of Iowa wax is flowed onto

the surface.

The patient is asked to repeat t, d, k, g, and attempt

swallowing.

b) The prosthetic tongue for swallowing

It is waxed in the form of a sloping trough like

base in the posterior aspect to help guide the

food bolus into the oropharynx.

Both types of tongue prosthesis may be fabricated as interchangeable speech and

swallowing prostheses attached via the retentive button on the base portion of the

prosthesis.


Mostafa Fayad

c) The mandibular tongue prosthesis which include both

features of swallowing and speech

In some instances, the mandibular tongue prosthesis

can be constructed to include both features of

swallowing and speech in a highly motivated patient.

Construction: The framework with the processed acrylic resin base

that contains the oral “mushroom projection” is used for this

purpose.

A heavy mix of Coe-Comfort tissue-conditioning material is

added to the base and the patient is asked to move the mandible

while pronouncing t, d, k, g as the material sets.

A trough like groove is created in the posterior middle aspect of

the traced tongue, with the aid of a speech pathologist.

The Coe-Comfort tracing is duplicated in silicone with

appropriate intrinsic coloration and attached mechanically on the

mushroom like projection of the acrylic-resin base.

speech can be improved by adding a flexible tongue of silicone rubber to the

mandibular prosthesis.

The body of the tongue prosthesis is held in place by developing a snap-ring and undercut

design in the mandibular denture base at the level of the occlusal table.

The tip of the tongue is flexible and elevated 2 to 3 mm above the denture base.

This position permits a positive contact with the palate during the formation of

linguoalveolar sounds and when the mandible approaches the closest speaking space.


Mostafa Fayad

Prosthetic Treatment of Partial Glossectomy

Indication:

Prosthodontic treatment for partial glossectomy is necessary when

the patient experiences difficulty in speaking and/or managing a

food bolus.

In cases where a patient has had a parital glossectomy and a partial

mandibulectomy; there is a greater need for glossectomy prosthesis.

Types: Either the palatal augmentation prosthesis or mandibular

augmentation prosthesis may be fabricated.

The function of the augmentation prosthesis is to fill the volume

deficiency between the remaining tongue and the mandible and the palate.

The choice between mandibular or palatal augmentation prosthesis depends

upon

the availability of abutment teeth,

the extent and site of the tongue deficiency,

Patient acceptance.

Mandibular Augmentation Prosthesis

Construction:

A conventional or interim mandibular removable denture is constructed

following the conventional prosthetic technique .

a thick mix of Coe-Comfort tissue-conditioning material is added to the

lingual flange in the area of the tongue deficiency.

The prosthesis with the Coe-Comfort is inserted into the patient’s mouth,

and the patient is instructed to swallow, open and close, and pronounce

certain phonemes depending on the site of the resection.


Mostafa Fayad

o Anterior resection situations require the use of consonant sounds

such as t and d,

o while posterior defects require glottal stop execution such as k and g

sounds,

the augmented part of the prosthesis is processed with autopolymerized

acrylic resin.

for an edentulous patient, the mandibular final impression is made utilizing the neutral

zone technique and the denture is processed accordingly.

Edentulous patient with partial resection of left tongue.

Mandibular augmentation prosthesis


Mostafa Fayad

Palatal Augmentation Prosthesis

The palatal augmentation prosthesis (PAP) has been defined as “A palatal

prosthesis that allows reshaping of the hard palate to improve tongue/palate

contact during speech and swallowing because of impaired tongue mobility

as a result of surgery, trauma, or neurological/motor deficits.

When using the palatal augmentation prosthesis, the

palatal vault is re-established at a lower level than

normal, requiring less bulk and mobility of the tongue

for appropriate palatolingual contacts during speech

and swallowing. The purpose of this prosthesis is the restoration of

deglutition, and speech potential in patients with

reduced tongue volume and movement .

Defining the contour of the palatal vault requires a compromise between

the needs for speech and swallowing, because the location and degree of

linguopalatal contact differ between these two processes. If the palatal vault is lowered sufficiently to permit optimal tongue

movement for swallowing, speech is adversely affected. If the palatal vault is shaped to optimize speech, tongue movement

during swallowing may be restricted. To alleviate the problem, the alternation between two magnetically retained

palatal vaults providing optimal linguopalatal contact for either speech or

swallowing was recommended.

Construction:

In dentate or partially dentate patients, a maxillary framework is

designed following conventional prosthodontic techniques with an

added mid palatal meshwork to retain the augmentation portion of the

prosthesis.


Mostafa Fayad

Functional molding of the augmentation portion of the prosthesis is

done during attempts at speech production, and a swallowing.

In the edentulous patient, conventional maxillary and mandibular complete

dentures are fabricated and used for a brief time (usually 2 weeks) before the

maxillary denture is augmented to compensate for the tongue deficiency.

A thick mix of tissue-conditioning material is added to the palatal

portion of the maxillary denture.

While the material is still moldable, the patient is instructed to

swallow and to pronounce certain phonemes, depending upon the

location of the deficiency.

A plaster matrix is fabricated and the tissue-conditioning material is

replaced with autopolymerized acrylic resin.

The palatal augmentation should be made hollow to reduce its

weight

Extraoral Maxillofacial Prosthesis

Mostafa Fayad


"It is the God given right of every human being to appear human". Ernest L. DaBreo

Introduction

Maxillofacial prosthetics is a branch of dentistry that deals with congenital and

acquired defects of the head and neck.

Maxillofacial prosthetics integrates parts of multiple disciplines including head

and neck oncology, plastic surgery, speech, and other related disciplines.

Method of restoration

Restoration of facial defects can be accomplished either surgically, prosthetically,

or by using a combination of both methods.

The choice of method depends on many factors such as size and location of the

defect, age of patient, mobile tissue (eyelid ,lip),

prosthetic approach has the following three main advantage

It requires little or no surgery.

The patient spends less time away from home and job.

The reconstruction often has a more natural appearance

The prosthetic approach is superior to the surgical approach if the defect is large

or the blood supply to the area is compromised

Superior color match and patient acceptance, especially in nasal or auricular

prostheses, make prosthetic rehabilitation superior to the surgical approach.

Drawbacks of prosthetic approach include

The necessity of fastening the appliance to the skin daily.


Mostafa Fayad

Removing the appliance daily.

The occasional need of constructing a new prosthesis.

Objectives of Maxillofacial Rehabilitation

1. Restoration of esthetics or cosmetic appearance of the patient.

2. Restoration of function.

3. Protection of tissues.

4. Therapeutic or healing effect.

5. Psychological therapy.

STANDARDS FOR FACIAL RESTORATIONS

NATURAL APPEARANCE

Correct form and size

Material must simulates normal healthy tissues with respect to : texture,

translucency, weight, and color

The molding material should have approximately the same flexibility as human

tissue in order to blend the margins of the prosthesis to adjacent tissues.

Prosthetic material should be sufficiently translucent to simulate skin effectively.

The color of the prosthesis must appear similar to the surrounding tissue.

RETENTION

Natural appearance also depends on holding the completed prosthesis in its proper

relation to the head

Retention of the extraoral prosthesis is limited to the resistance of gravitational

forces and the weight of the prosthesis . see retention of maxillofacial prosthesis


Mostafa Fayad

COMFORT

The wearer of the prosthesis must be able to depend on comfortable attachment of

the prosthesis to the tissues for extended period of time.

The fitting surface must be formed to fit closely to the tissues and to be free of any

rough areas that can cause irritation .

DURABILITY

The durability of a facial prosthesis is primarily dependent upon both prosthetic and

human factors

selection of proper materials and fabrication techniques

mental attitude of the wearer

All users of prostheses must be properly trained and instructed in the wearing and

care of the prosthesis at the time it is being fitted and delivered.

Disease in an area previously afflicted may recur causing tissue changes and

requiring the rebuilding of the prosthesis .

Evaluation and Treatment Planning

Preoperative evaluation of the patient, as with any head and neck cancer patient

provides for optimal preparation of the patient and planning of the treatment.

A good oral hygiene protocol is mandatory for dentulous patients. Preservation

and restoration of such teeth may provide a much better fitting prosthesis. In case

of combined cases

Effective communication between the surgeon and the maxilloacial prosthodontist

is essential for developing a realistic treatment plan or rehabilitation of patients

undergoing resection .


Mostafa Fayad

The team concept, in which the head and neck surgeon, speech pathologist,

radiating oncologist, maxillofacial prosthodontist, and other members of the health

profession function together in planning the rehabilitation and primary modes of

therapy, ensures the patient's early and successful rehabilitation.

Prognosis:

Patients should be informed of the many variables that influence the course of

treatment and treatment outcome.

Care should be taken in preparing the patient for a realistic treatment result,

emphasizing the limitations of prosthetic treatment in simulating the natural

missing structures

Patient assessment

Case history

Optical &dental checks

Clinical assessment

1. The size and extent of the planned prosthesis

2. The optimum position of leading margins

3. Identification of mobile and supporting soft tissue

4. Sensitive or tender areas

5. Area of hypertrophic scarring

6. Needed preprosthetic surgery (thinning or releasing), reshaping, or removal of redundant tissues

7. X ray


Mostafa Fayad

Facial Prosthetic Material

The materials used in the different phases of the fabrication of the maxillofacial

prosthesis are : impression materials, modeling materials and fabricating materials .

I- Impression materials

the manner of setting non - elastic materials elastic material

Set by chemical reaction

“irreversible”

Set by temperature change

Plaster of paris

Zzinc oxide - eugenol and

similar pasts

Peripheral seal materials

Impression compound ‘composition’

Impression wax

Gutta percha

Irreversible hydrocolloid “alginate”

Elastomers:

Reversible hydrocolloid “Agar”

The chemistry, manipulation, properties and applications of each material is discribed in

details in the text books of dental materials. The clinical techniques will be described

later in chapter two and in other chapters according to the type of prosthesis.


Mostafa Fayad

II- Modeling materials

The modeling materials should have the following intrinsic properties.

1- They should be malleable to facilitate contouring and adjustments.

2- have sufficient body and strength to permit sculping and withstand slight abuse.

3- It should be possible to sculpt texture into this material which will be imparted to the finished mold.

4- The closer the color of the material in to skin tone.

5- It should be inexpensive and available.

The Commonly Used Modeling Materials Are:

1- Modeling Clay (Sculptor’s Clay)

A water-base clay which, when allowed to dry, becomes a hard stone-like substance.

Advantages

1- Consistency can be adjusted by adding water.

2- Lends itself to gross sculpting of sweeping planes.

3- Takes texture well.

4- Can be feathered on the edge.

5- Readily available.

6- Inexpensive.

Disadvantages

1- Must be kept moist at al times. If allowed to dry it tends to crack and flake.

2- If the modeling must be set aside for any length of time the cloth utilized to keep it moist tends to wipe out the finer texture which has been incorporated into the model.

3- It is gray in color, and the color differential causes visual distortion.


Mostafa Fayad

2- Plaster

Advantages


2- Easily and quickly prepared for use.

3- Can be shaped or molded in its plastic state.

4- Inexpensive.

Disadvantages

1- Lacks elasticity.

2- Cannot be used in undercuts .

3- Relatively short setting time.

4- Has a tendency to flake on the surface.

5- Adding materials to build contour is difficult.

3- Plastolene

A prepared modeling clay with oil base or fuller‘s earth with oil base

Advantages

1- Always ready for use.

2- Requires comparatively little care.

3- Easily malleable.

4- Takes texture well

5- Withstands slight abuse well.

6- Can take and keep a feather edge.

Disadvantages

1- Color does not match skin tone .

2- Oil base could seep into stone model and affect the finished product..

3- More expensive than sculptor‘s clay.


Mostafa Fayad

4- Waxes

Advantages

1- Color is similar to skin tone .


3- Takes texture well.

4- Easy to smooth .

5- Withstand abuse.

6- Takes and keeps a feather edge.

Disadvantages

1- Model must be carved rather than sculpted.

2- Oil base could seep into stone model and affect the finished product.

3- Brittle when cool.

The choice of modeling material should depend upon knowledge and experience with the

materials. The patient should be present during the modeling phase. Any discrepancies in

the model can then be picked up and corrected before making the final molds.


Mostafa Fayad

III – Materials used in fabrications of

maxillofacial prosthesis

The materials used for fabrication of maxillofacial prosthesis should have specific

physical and chemical requirements depending upon the anatomic location and the main

purpose for which the device is designed. Thus the requirements of a material for an

intraoral prosthesis are quite different from those for an extraoral prosthesis.

The basic requirements of material for intraoral prosthesis:

1- Tissue Tolerance

It must have a smooth surface, be non-irritating and compatible with oral tissue.

2- Strength and Durability

The material must be sufficiently strong and rigid to withstand forces of

mastication and to resist distortion over a period of time.

3- Proper Thermal Conductivity

The thermal conductivity of the material should not be too high or too law.

4- Nonsorption

The material must resist sorption of moisture present within the oral cavity, such

as saliva, water, and fluid food.

5- Cleansability : The material must be readily cleaned and hygienic

6- Integration with other materials without injury to either component.

7- Ease of casting, molding or processing.

8- The material should has a cosmetic appearance.


Mostafa Fayad

The basic requirements of extraoral prosthetic material:

1- Tissue Compatibility

The material should not irritate or injure the tissue upon which it is rest.

2- Flexibility

The material must be soft and pliable like flesh and skin to simulate the feel of

facial tissues.

3- Translucence

The material must be translucent, that is, its light -transmitting quality must be

similar to that of the skin. Translucence of a material offer greater significance in

those case in which the lifelike coloring can be attained best by coloring the

material intrinsically rather that extrinsically.

4- Lightness

The material must be light in weight so that little difficulty will be encountered for

keeping the prosthesis properly and securely in place.

5- Durability

The material must not be affected physically or chemically by the tissues in

contact with it, or by the adhesive used for its retention

6- Thermal Conductivity

The material must be a poor conductor of heat to avoid irritation of the tissues

when rapid and considerable change in temperature occurs.

7. Color stability


Mostafa Fayad

8. Ease of Processing

The material must be readily amenable to molding or casting by techniques

employed in a dental or similary equipped laboratory.

Actually most extraoral prosthesis prepared by the maxillofacial prosthetist

usually require the use of special apparatus.

9. Ease of Duplication

The material must lend itself readily to duplication by use of either the original

permanent mold or a master model so that in case of loss, discoloration, or general

deterioration of the prosthesis a new duplicate can be made with minimal effort

and expenses.

10. Availability

The material should be available in the market and inexpensive.

11. Hygienic

It should be easily cleaned without damage or deterioration.

The materials used in maxillofacial prosthetics may be rigid materials and / or

flexible materials.

12. Minimal conductivity

13. Edge strength


Mostafa Fayad

The materials formerly and currently used for construction of

extraoral prostheses

Rigid Materials

Generally rigid materials are more useful in the fabrication of intraoral prostheses

except in certain areas of denture prostheses coming in contact with sensitive

intraoral areas, or areas with undercuts.

Flexible Materials

Flexible materials is considered the material of choice for facial prosthetic

restorations except for some workers who prefer a rigid material for facial and

certain other extraoral prostheses.

The advantages of flexible materials over rigid materials for facial prostheses are:

1- Its natural feel when in contact with tissues, ease of fit and adaptability to the

irregularities and undercuts at the site of deformity.

2- Ability of the edges of the prosthesis to respond in some degree to the movements

of adjacent parts of the face.

3- Ease of its removal after casting from a rigid mold, which allows keeping the mold

intact for future use.

4- Its adaptability for producing hollow and lightweight prostheses by the so-called

slush molding technique.


Mostafa Fayad

Classification of materials used for construction of extraoral

prosthses

This classification includes those not in use today only because of the historic interest,

and occasional usefulness of them today.

Rigid materials Flexible materials

Materials of limited interest

1-wood & Ivory.

2-Metals.

a-Copper, Silver, or Gold and their alloys.

b-Aluminum.

3- Vulcanite.

4-Cellulose plastics.

a-Cellulose nitrate.

b-Cellulose acetate.

Materials of major Interest

Acrylic plastics.


1-Gelatin-glycerin mixtures.

2-Latex and its derivates (Rubber).

a-Heat curing variety.

b-Room temperature curing variety

(prevulcanized liquid latex).

Materials of major Interest

1-Plasticized plastics.

2-Slicone rubbers.

a-Heat curing variety.

b-Room-temperature -curing variety.


Mostafa Fayad


Wood and Ivory

These materials have excellent tissue compatibility but the law thermal

conductivity and poor pliability, translucence, cleansability and molding ability

make them not use today.

Metal or Metallic Alloys

Prostheses made from metal or their alloys are very durable and light in weight as

they can made hollow. These types of prostheses are difficult to fabricate “by

casting swedging or electrodeposition” and the results are not lifelike owing to

their opecity.

The advantages of these prostheses are that they can be soldered or locked to some

other prosthesis in the maxillofacial region to aid retention. Also the strength and

the smooth surface of metal make it a material of choice for certain intraoral

maxillofacial prostheses

Vulcanite

In the late 19th century, certain workers began using vulcanite for constructing

facial restorations. The surface of this material was painted in order to match the

color of the skin.

It is a rigid material which was used extensively in making a full denture and in

prosthetic reconstruction of the face before the introduction of translucent rigid

plastics. Its ease of molding compatibility with the tissue and comparative strength

and lightness are some of the characteristics that made it suitable for facial

prosthesis in early days. Its lack of translucence is its chief objectionable feature.


Mostafa Fayad

Cellulose Plastics

cellulose nitrate or cellulose acetate (celluloid. Are earlier plastics that can be

molded between dies and counterdies to produce a very light weight prosthesis.

Hand painting must be done to give the prosthesis a realistic appearance.

Gelatin, glycerin mixture

The esthetic results of this material is good, it is simulating the pliability, texture,

and translucence of the skin. The prosthesis made from this material last only a

week at most. So it could be used in an emergency for fabrication of temporary

prosthesis.

Rubber

Conventional rubber produced by compounding the latex with sulfer and

valcanizing it under heat and pressure. This process needs heavy and expensive

equipment not available in an ordinary dental laboratory. So its never have wide

application in maxillofacial prosthetics.

Prevulcanized Latex

This type of liquid rubber can be poured into a plaster mold and that, upon drying,

is converted into tough rubber. The use of this type of latex elemenate the need of

expensive metal dies for molding and hence this material has proved very useful in

facial prosthetics.


Mostafa Fayad

Materials of Major Importance

A- Acrylic Plastics

Methyl Methacrylate :

Either heat or self (poly) methyl methacrylate ,which used

for denture bases, may be used for certain types of

extraoral prostheses, especially when strength and

durability are desired. Repairs of or additions to the acrylic

prostheses are not difficult.

Palamed :

Palamed is a cross-linked copolymer of methacrylics and acrylics. It consist of a

powder and liquid which, when combined form a doughlike material. This

material is packed into a closed mold and cured in a hot water bath. When

processed, the prosthesis has a spongelike center and a continuous skinlike

covering. The molds should be underfilled (by 10%) to permit expansion of the

material and formation of the spongelike center.

The thicker section of the prosthesis are quite elastic, but the thinner one will be

more plastic, since the center portion of the thinner sections is less foamlike.

Removal of the prosthesis from the mold after processing is a delicate procedure

which can be facilitated by dipping it into warm water (45 C for 10 minutes)

thereby softening the prosthesis.

B- Plasticized plastics

These plastics owe their resilient character to the presence of a plasticizing agent

in the resin. Pigments may be add to obtain the suitable color. These materials are

usually set by heating. These materials gives better pliability, tranlucence, color

and flexibility that are so desirable for facial prosthesis.


Mostafa Fayad

Plasticized vinyl plastics are the most commonly used materials in facial

prosthetics. These materials are

Vinyl Chloride (polyvinyl chloride - PVC),

It is copolymer of Vinyl Chloride and Vinyl Acetate (the

monomer of these two materials are mixed in proper

proportion and polymerized ) this material has excellent

molding characteristics.

The main disadvantage of the plasticized plastics is that they become hard by

migration of the plasticizing agent out of the plastic.

PVC hazardous to health and the environment. They argue that PVC plants emit

toxic pollution during its production and that products made of PVC emit toxic

compounds during their usage and in disposal. This is due to toxic chemicals

added to it in production.

e.g. Realastic and Mediplas..

Realastic

It is a polyvinyl chloride compound (PVC) which solidifies into a flexible material

when heated. Tinting can be accomplished both internally and externally,

Ultraviolet light causes a combining of organic chains and subsequent yellowing

and hardening of the material. The manufacturer has recommended a cream

conditioner, to be applied nightly to the prosthesis, which seems to prolong its life.

However, use of this cream on the margins will affect the retention because the

adhesive will not adhere to the prosthesis.

Because of the short life of this material, metal molds are suggested so that

additional prostheses can be made from the original model. The main disadvantage

is the additional time required to make metal molds.


Mostafa Fayad

Mediplas

Mediplas is a heat-curing plastisol that is basically a polyvinyl organic compound.

It can be cured within a stone mold, but the use of metal molds is recommended

which facilitate the many remkes necessitated by the short life of this material.

About 10 minutes at 140 C is required for curing this material in an open plaster or

metal mold. When closed plaster molds in standard dental flasks are used, the

curing time is about 2.5 hours.

Overheating should be avoided during curing because this material has a tendency

to darken when exposed to excessive heat. However if undercured, it may cause a

skin reaction.

The material loses part of its flexibility because of absorption of cosmetics and

adhesives, which neutralize the plasticizer.

Replacement time for this prosthesis would be very short, especially with the

exposure to sunlight. This material is most appropriate for persons who spend

most of their time indoors.

C- Silicone Rubbers

These materials retain their original pliability for longer periods. It is extremely

inert and does not deteriorate.

There are two basic variations of silicone rubber (based on the manner of

processing):

- Heat cured silicone.

- Silicone cured by addition of an activator to the uncured material..

The complexity of the heat cured process precludes its use in most prosthetic

laboratories.


Mostafa Fayad

Room-temperature vulcanizing (RTV) silicone rubber are now used successfully

in maxillofacial prosthesis. e.g. Silastic 382, Silastic 399, and Dermasil.

Silastic 382 (RTV)

It is a medical grade silicone rubber material supplied in the form of a thick white

liquid with separate container of an organometallic catalyst.

When the catalyst combined with the rubber, vulcanizes it without the use of heat

or pressure.

The working time of Silastic can be varied from 2-60 minutes by adjusting the

amount of the catalyst. The catalyst and rubber are mixed on a flat surface to

minimize the inclusion of air bubbles. Silastic 382 can be molded without

difficulty with simple bench press pressure, or the material can be poured. Repairs

can be made to this material if the surface is cleaned meticulously with xylene and

a fresh mixture of material added.

Internal coloring may be difficult because the raw material is white. To overcome

this problem and to increase the translucency, clear silastic S5392 can be used.

Edge strength of silastic is a problem, and the use of white nylon stocking material

embedded in the prosthesis will give added strength.

To decrease the weight of the prosthesis, a foam type silastic (S5370) can be used

for the internal portion of a thick prosthesis. Mechanical retention employing

undercuts, magnets, or other means is preferred than the use of adhesive to

prolong the life of the prosthesis. The average life of a silastic prosthesis is about

6-8 months.

Silastic 399

It is a RTV rubber which has all properties of silastic 502, the great difference

being color. Silastic 399 is in the form of a clear gel, which makes tinting


Mostafa Fayad

appreciably easier. Two catalysts are also required with this material , which

makes this procedure no more difficult but requires more time.

Dermasil

It is a self-curing silicone in which catalyst is used to initiate the reaction. It is a

clear base material in which ground pigment is added to obtain the proper shade.

The difference between the appearance of Dermasil while it is being mixed and

when it has been cured makes test samples highly desirable. The last samples

should have the same thickness as the prosthesis in order to determine if the

overlay of color will produce the needed color or not.

The margins are fragile and should be reinforced with nylon stocking material.

In painting the color into the mold., speed is a factor. If one section of color is

allowed to set before the other is added, the finished prosthesis will have a

splotchy appearance.

Extrinsic color is desirable if it is applied by means of an air brush, but if the

coating is applied too thickly, it becomes extremely glossy and appears artificial.

1900-1940 vulcanite, latex, and gelatin and glue mixtures had been tried for these

prostheses but they were deficient in several aspects.' These earlier materials were not

flexible enough. Trials were carried out to test various types of synthetic plastics,

however, polyvinyl resins proved the most successful.

In 1937 Acrylic resin Prosthesis replace vulcanite & pvc material

In 1953, a group of dentists founded the American Academy of Maxillofacial

Prosthetics.

1960-1970: introduction of elastomers and silicon rubber

1970-1990: modified polysiloxane elastomer & polyurithane elastomer


Mostafa Fayad

1990 till present: new generation of acrylic resin , polyphosphazenes (permanent

resilient denture liner),, and silicone block copolymer (j prosthod: January 2010, review of

maxillofacial materials)


Mostafa Fayad

Impression Techniques

The success of maxillofacial prosthesis is actually depends upon the taking of an accurate

impression of the existing deformity. From this impression a positive cast is made.

Interoral impression techniques

The techniques of obtaining accurate intraoral impressions is well known.

However, the variation in the patient’s preoperative or postoperative oral anatomy

should be considered. Incomplete palatal closures are often present and these

should be blocked out with lubricated cotton or gauze to which a piece of dental

floss has been tied.

The areas need blocking out prior to impressions are determined by careful

examination, and the guideline should be, ”when in doubt about undercuts and

impression removal pack the defect“.

The defect may also require some special addition or correction to the tray. This is

done by adding periphery wax or hard stick compound to build the try up or out to

capture the anatomy as needed.

Extraoral impression techniques

The obtaining of facial impression (mask) and preparing a working model

(moulage) is important to fabricate facial prosthesis.

The impression materials vary in the end result.

-Reversible hydrocolloid or plaster of paris give the best accuracy.

-Irreversible hydrocolloid or silicone gives good detail quickly.

-Orthopedic plaster bands or impression compound produces general contours, but

not very much detail.


Mostafa Fayad

Patient preparation before facial impression

Patient position:

The patient should be reclined in a dental chair or, better, lying on a table with his head

slightly elevated. This position achieves a relaxed muscle tone of the face and easier

material application.

Preparation of patient:

1-The patient is draped with a sheet and the hair is

boxed out leaving the areas to be reproduced

uncovered.

2- The face should be free of make-up and eye-

glasses.

3- The eyelashes, eyebrows, mustache, beard, etc. should receive a coating of

separating medium as petroleum or cocoa butter.

4- The undercuts of the defect and the nostrils are blocked out with wet gauze or

cotton.

5- The face or the part to be reproduced should be boxed in with red wax strips

held in place by an assistant.

6- An adequate airway is maintained with straws into nostrils or mouth, or with

care, a small amount paint brush can be gently used to apply the impression

material to the nose up to but not including the nares.


Mostafa Fayad

Reversible hydrocolloid

The hydrocolloid is applied using a small paint brush ,to build up a thickness of 3

-4 mm of the material. Before complete setting of the hydrocolloid L-shaped paper

clips are added ( only one end of each paper clips is imbedded into the material ) .

After cooling in about 5 minutes, plaster of paris is applied to a thickness of 8 to

12 mm to reinforcement the hydrocolloid via the paper clips (Fig. 2-4). After the

plaster set the patient is asked to wrinkle his face to loosen the impression. The

boxed impression is removed and checked. The impression is placed in cool

water until poured into stone to form the moulage.

A. Reversible hydrocolloid is applied to the face. B. L- shaped clips is added. C. Plaster

of Paris is applied. D. Impression is removed.

Moulage made from the impression .


Mostafa Fayad

Irreversible hydrocolloid

The technique is similar to the reversible hydrocolloid with some variations that

the alginate powder is mixed with cool water. Excess water should be used to help

the material to flow readily into all depressions. The material is poured over the

face and pushed into the desired areas with brush or spatula. L-shaped paper clips

are inserted before the material set.

Plaster of Paris is applied after the material has set. After removal of the

impression the mask is rinsed and immediately poured up, using stone.

Silicone

The use of room temperature-vulcanizing (RTV)silicone is more expensive than

any other material. However the material has the following advantages:

-Gives good detail of the face.

-Many pours can be made if needed.

-can be stored easily with little deformation.

The use of this material is very easy, the material is applied directly to the face

with spatula to make thin build-up. Thin layer of gauze are applied all over with

light pressing into place for reinforcement, then more silicone is added. After

setting of the material the impression is removed and poured.

Plaster of Paris

This material gives excellent accuracy but it should not be used when the defect is

fresh, or where deep undercuts exist.

A light petroleum casting is applied to the whole area of impression. The plaster

should be thinly mixed and painted on the face. Papaer clips are not used, the

plaster is added and built up. The plaster is allowed to harden initially, then


Mostafa Fayad

removed before its exothermic stage is reached. Separating medium should be

applied to the mask before pouring the model.

Orthopedic plaster band

This material is not register the fine details of the face and the resulting moulage is

fine for constructing radiation-protector shields.

The orthopedic plaster band are cut to the width of the face while they are still dry.

Six strips are dipped in cool water and contoured over the lubricated face. Once

set, the mask is removed and separating medium is applied before the model is

poured.

A. Orthopedic Plaster band is applied to the patient face. B. Built up of additional layers.

Impression compound

This material gives rapid but rough impression. The moulage obtained is fine for

construction of radiation-protector shield.

The compound is warmed, flattened to the size of the face,and applied to the face

with light adaptation. After few minutes the compound mask is removed and

poured.


Mostafa Fayad

Recent advances in modeling of extraoral defect

Journal of Indian Prosthodontic Society | December 2005 | Vol 5 | Issue 4

Drawback of conventional impression techniques

Patient discomfort.

Displacement or distortion of the soft tissues.

Time consuming in modeling and carving.

The technique relay upon the operator skill and individual ability.

The basic steps involved in automated fabrication of extraoral prosthesis composed of 3

phases

1. Collection of 3-D anatomic data(3-D facial measurements) using scanning techniques

Computerized Tomography (CT) Scanning

Magnetic Resonance Imaging (MRI) Scanning

3-D Optical Scanning

2. Generation of 3-D computer model (blueprint) of the extraoral defect

3. Manufacture of physical prototype.

Computer Numerically Controlled (CNC) milling

Rapid Prototyping


Mostafa Fayad

Collection of 3-dimensional anatomic data using scanning

techniques

Computerized Tomography (CT) scanning

Advantages and Limitations

Computed tomography scans are readily available.

The use of CT scans allows parts of the body to be serially recorded slice

by slice. The 3-dimensional computed data obtained can be used to

construct an anatomic model or prosthesis of exactly the same dimensions

and geometry of the deformed side of the face.

Limitation of CT: The use of CT scans to obtain 3-D anatomic data cannot

be ethically justified because of the high dose of radiation administered.

Magnetic Resonance Imaging (MRI) scanning

Advantages and Limitations

Magnetic resonance image scanning is a non-invasive (zero radiation)

alternative that projects a 3-dimensional image of the soft tissues together

with bone.

The possible disadvantages remain the length of time the patient is required

to remain motionless during the entire length of scanning and the high cost

entailed.

A further exclusion of this method would arise when many stainless steel

wires have been previously used to secure jaw fragments in corrective

surgery.


Mostafa Fayad

Optical scanning

The optical 3-dimensional (3-D) scanning unit provides a point cloud or virtual model of

the face.

Two main types of optical scanning were used

1. 3-D scanner based on self calibrating fringe projection technology (“Kolibri-

mobile”)

2. 3-D laser scanning system

The requirements of optical scanning include

1. The body part (for example, the face) should be viewed from different directions

simultaneously

2. The measurements should be made within seconds

3. the system should be mobile and simple to use

3-D scanner based on self calibrating fringe projection technology (“Kolibri-

mobile”)

It is a mobile, multiview 3-D measuring system

that facilitates the fully automatic recording of the

body part from various directions in one

measuring process.

The maximum field diameter of the system i.e. the

area that can be recorded at one time is 650 mm.

Therefore, the complete human face can be

recorded in a single operation.


Mostafa Fayad

Advantages

a. The system is mobile.

b. Simple to use.

c. Measurements are made within seconds (approximately 20 seconds)

d. The complete human face can be recorded in a single operation.

e. The procedure avoids the stress experienced by patients when conventional modeling methods are used.

f. Avoids exposure to radiation when using a CT or MRI.

3-D laser scanning system

The system based on 3D eye-safe laser scanners

A laser scan of the full face takes 30 seconds and is a non-invasive

means of collecting digitized data.

The laser scanner and CAD/CAM systems used in the fabrication of

auricular prosthesis in the late 90’s.

Some of the constraints to the use of this technique remain loss of some information of

the ear caused by light reflection from the hair and inaccessibility of the internal undercut

surfaces of the ear by the vertically projected lines of the laser beam.

These problems were overcome by a 3-D laser scanning system developed recently to

produce a 3-D dental cast known as “emodel”.


Mostafa Fayad

Generation of a 3-D Computer Model (“blueprint”) of the

extraoral defect

Once accurate geometric information of the defect is collected using the scanning

techniques, the information is imported into the scanning systems proprietary

computer –aided design (CAD) software package for manipulation and the

production of a “blueprint” (CAD model) from which the prototype is

manufactured.

Manufacture of a physical prototype

Computer Numerically Controlled (CNC) milling

Data obtained by optical laser scanners have been used in conjunction with

computer software which converts 3-D data sets into an instruction sequence for a

CNC milling machine to prepare a reverse model of the normal ear.

Limitations

Milling machines reproduce only the outer surface contours. The details

of the internal geometry (undercut contours) are created by freehand –

carving (by the technician). These limitations led to the development of

rapid prototyping techniques.

Rapid Prototyping (RP)

it operates on the principle of depositing material in layers or slices to build up a

model rather than forming a model from a solid block thus offering a great

advantage of creating all the internal geometry as well rather than just the outer

surface contours as with a milling machine.

There are currently many variants that are marketed, but the 3 dominant

technologies include:


Mostafa Fayad

a. Stereolithography: uses an ultraviolet laser to solidify a liquid plastic (resin)

layer by layer

b. Laser sintering: uses a laser to selectively fuse a thin layer of powered plastic

or metal to previously fused layers and;

c. Laminated object manufacturing: laminates thin sheets of material

successively and cuts and destroys material with a laser, leaving behind a

solid laminated part.

In each of these techniques, the layers added can be thinner than 0.5 mm with a vertical

wall thickness of as low as 0.2 mm.


Mostafa Fayad

Nasal Prosthesis

Because it is a single entity (that is, there is no contralateral equivalent as with eyes and

ears), the nose is the easiest and technically simplest prosthesis to fabricate.

Ideal requirements of material used for nasal prosthesis:

1- Esthetics:

o Produce fine details.

o The same color, texture, form and translucency.

2- Fabrication:

o Easy manipulation.

o Suitable working time.

3- Physical properties:

o Strong enough.

o Sufficient flexibility (used on movable tissue

bed).

o Dimensional stable.

o Light in weight.

o Suitable edge strength (permit thinning or fathering margins).

o Low thermal conductivity.

4- Biological and chemical properties:

o Resist various chemicals.

o Stable with salivary and nasal secretions and adhesives.

o Non toxic and non allergic.

o Biocompatible.

o Durability.


Mostafa Fayad

Restoration of nasal defects:

Nasal defects occur 2ry to: neoplasm – trauma.

Most of partial nasal defects restored with surgery.

Most of total nasal defects restored prosthetically.

Presurgical consultation with surgeon is important to defect, if the

defect is to be permanently or temporary restored with a prosthesis.

1- Partial Rhinectomy Defects:

The surgeon may restore the defect temporarily with a prosthesis in order

to delay the surgical construction after the observation period is elapsed.

Covering the defect with local flap may delay discovery of the recurrent

tumor (basal cell carcinoma) which cause metastasis and destruction of

local adjacent tissues.

2- Total Rhinectomy Defects:

Prosthetic restoration are preferable than surgical recontouring.

The surgeon is advised to remove the nasal bones and the rest of the nose to

make it ideally (flat or concave surface) to make the prosthesis that

duplicate presurgical nasal contours.

Placement of split-thickness skin graft over exposed area is preferable.

Patient should be informed about benefits and limitation of the prosthesis.

Photographs of patients with similar defects may be used to educate the

patient.

Conversation with the rihnectomy patient who is wearing nasal prosthesis

may be helpful.

Patient expectations to the prosthesis should be realistic.


Mostafa Fayad

Family members encourage to be present during consultation.

Psychological consultation and evaluation should be short before resection.

Before resection, facial impression and photographs should be obtained.

Before taking impression, the undesirable undercuts should be blocked out

with gauze.

Types of nasal prosthesis:

1- Temporary nasal prosthesis:

- The wound is sufficiently healed (3 - 4 weeks) after surgery, this allow for

placement of temporary nasal prosthesis.

- Patient is happy so, he can resume the social interaction and return to work.

- The material of choice is (heat polymerized methyl methacrylate), because:

a) It can be retained with temporary denture liners.

b) Allow for scar contraction and organization of wound.

- Retention of the prosthesis is aided by medical grade skin adhesive.

- The wound is sufficiently contracted and organized soft tissue bed is

formed (3 – 4 months) after surgery, this allow for fabrication of definitive

prosthesis.

2- Definitive nasal prosthesis:

- Flat defect with intact nasolabial fold is the best to restored.

- Retaining the nasal bones compromise the contours of the finished

prosthesis.

- Defect with surgical margins out of the nasolabial fold may be difficult

to restore due to exposure of the line of junction.

- Margins onto the upper lip may be masked with facial hair.

- Definitive prosthesis with flexible material are:

a) More comfortable to the patient.

b) Retained in position for long period, especially if patient have

highly mobile soft tissue bed.


Mostafa Fayad

Procedures:

- Impression making:

1- It is advisable to take impression with patient in upright position. Because,

horizontal position will distort the soft tissue bed.

2- Elastic impression material (irreversible hydrocolloid)

Alginate is used and thinned to increase flow by adding

50 % water more than usual.

3- Opening of the nasal passage should be blocked with

gauze to prevent escape of material to the nasal passage

(asphyxia).

4- A facial cast is made, then master special tray is

fabricated and confined to the defect area.

5- Using a syringe we inject the flowable material in the undercut areas. But,

take into consideration not to compress the soft tissue bed.

6- Load the special tray with impression material in position. The excess

material should be removed periodically by index finger.

7- When the impression is set it will be removed and poured by dental stone to

fabricate the master cast.

- Wax pattern carving:

1- It is important in carving to produce the same contour, texture and proper

placement of the line of junction.

2- If presurgical cast is not available, the wax is adapted to cast and basic

contour is done.

3- Patient should have multiple presurgical photographs for reference.

4- It is preferred to have a family member during carving for better perception

of contours than the patient.

5- Ala of the nose should be in a proper location in relation to nasolabial fold.


Mostafa Fayad

6- Care must be taken not to make the nose wide in Alar region (equal to

inter-canine distance).

7- Nares should be symmetrical and resemble the presurgical contours.

8- Junction between Columella and skin should be right angle or acute angle,

in order to be difficult to seen under the tip of the nose.

9- Tip and Dorsum of the nose should be resemble presurgical contour.

10-The bridge area shouldn't be wide and this is verified by wearing of eye

glasses.

11-Eye glasses frames may improve appearance, if possible margins of the

prosthesis extend to mask the superior and lateral margins beneath it.

12-If we can't mask the margins for any reason, care should be taken to feather

the margin of the nasal prosthesis. i.e. (smooth transition between the skin

and the prosthesis).

- Processing:

1- Wax pattern is invested in suitable mold material.

2- Basic shade of the prosthesis should match the lightest color in area.

3- If the basic shade is darker, it will be impossible to have esthetic match.

4- Extrinsic coloration done under presence of the patient and under good

light.

5- Evaluation of coloration under varied (different) light sources.

- Delivery:

1- Hollowing the inner surface as much as possible decrease the weight of the

prosthesis.

2- Retention is achieved by using medical grade skin adhesive.

3- The patient must be followed up periodically.


Mostafa Fayad

3- Partial Nasal Prosthesis:

- Fabricated as the same way as total nasal prosthesis.

- More line of junction will be exposed than total nasal prosthesis.

- For achieving good esthetic results, it should be carefully colored and feathered

to mask the transition between skin and prosthesis.


Mostafa Fayad

Eye prosthesis

Anatomy:

Occular Prosthesis: It is a plastic prosthesis used when an eye is surgically

removed. It is an artificial replacement for the bulb of the eye.

SCLERAL SHELLS: A scleral shell is an ocular prosthesis that is worn over an

existing eye

Orbital Prosthesis : Replaces Eye and surrounding tissues

When the entire content of the orbit (including muscles fascia, eyelids, conjunctiva

and the lacrimal apparatus) is removed, the artificial replacement is referred to as

an orbital prosthesis.


Mostafa Fayad

Conformer: It is a temporary clear plastic prosthesis used after surgery to

maintain the size of the socket.

Ocular prosthesis

The artificial eye is made of acrylic (polymethylmethacrylate)

Component of artificial ocular prosthesis

1- PMMA powder with intrinsic pigments in order to replicate

the base colors of the natural sclera

- clear PMMA

2- PMMA corneal-pupil piece

3- Prefabricated iris button

The position of the iris was determined with the help of landmarks make the patient look

in a straight to line

A layer of clear plastic is added to seal in the painting and provide the glossy appearance


Mostafa Fayad

Materials of construction:

a) Plastic acrylic eye:

Advantages:

1- Not fragile as glass and don't cause etching sensation.

2- It is custom made → easy to adjust size, form and contours.

3- Easily adapted to individual esthetic requirements.

4- Actual 3 dimensional effect in Iris construction.

5- Perforated Iris buttons can be socketed.

6- Permits elimination of time consuming steps → as multiple mold

construction.

7- Method is easy to teach.

b) Glass eye:

Disadvantages:

1- Extremely fragile → may explode in eye socket.

2- Glass interact with fluid of the socket.

3- Difficult to fit properly in relation to defect.

4- Giving the wearer the appearance of Exophthalmoses.

Examination of eye socket:

1- Knowledge of the anatomic features of the eye is essential.

2- Existing muscle movements should be studied.

3- Type of operation by the surgeon: enucleation – evisceration.

4- If there is implant sphere was embedded at the time of surgery or not and what the

type of its material (gold – glass).

5- The amount of orbital adipose tissue present.

6- Extent of muscle atrophy.

7- Contour and tonus of the eye lids.


Mostafa Fayad

Technique of fabrication of the ocular prosthesis:

1- Painting of the Iris disk.

2- The Iris button.

3- The wax form.

4- Molding.

5- The sclera.

6- Veining technique.

7- Conjunctiva.

8- Polishing and fitting.


Mostafa Fayad

Clinical Procedures:

- 2 methods were stated:

a) The most commonly used → make a scleral pattern from stainless steel ball

bearing.

b) Using alginate impression to register the contents of enucleated socket.

- It is important for surgeon to place a conformer in the socket after enucleation

(except when unusual amount of hemorrhage) → made of acrylic → must be large

enough to support eye lids and keep them from collapsing until construction of the

artificial eye.

-

a) Scleral pattern from stainless steal ball bearing:

1- A ball bearing is selected as sphere to make the scleral pattern.

2- Hard base plate wax is softened over the Bunsen flame and compressed over

the ball bearing.

3- It is very important to relief the wax against the (Whitnall's ligament).

4- The wax pattern is trimmed to proper size and shape → tried in socket.

5- The center of the Iris → marked on the wax.

6- The Iris button is fixed to the hard wax cup using soft green wax.

7- Make any correction to place Iris into proper alignment and position.

8- Special yellow high heat wax is used to buildup smooth and spherical

prosthesis.

9- The prosthesis tried in the socket to check for: optimal lid form, mobility and

Iris line up.

b) Registration of socket using alginate impression:

1) Making Impression:

Preparation of the patient:

1- The hair is boxed out by using cloth towels.

2- The face should be free from make up and eye glasses.


Mostafa Fayad

3- The facial hair should be isolated by a means of separating medium.

4- The eye brow and supra-orbital tissue of the defective eye are retracted.

5- Full width of the face (1 inch above eye brow and to upper lip) is boxed.

6- Patient instructed to close his remaining eye and breath through his mouth.

Impression procedure:

1- Using reversible hydrocolloid (50% water : 50% impression).

2- When material are heated to proper temperature, consistency and ready to

be used → the operator tests the material with little finger for proper

temperature before applying over patient skin.

3- The impression material is painted on patient face with camel's hair brush

→ starting from undercuts and point of the greatest depth → then the entire

box area → building up at least 3 mm layer of material.

4- Pre bend L-shaped clips is inserted for reinforcement.

5- Wait for 5 minutes for setting of impression and proper reinforcement of

clips.

6- Sufficient thickness of Plaster of Paris is poured → removed after initial

setting by asking the patient to wrinkle his face and put in cold water → to

prevent cracking of impression under exothermal setting of Plaster.

7- Check accuracy of impression.

2) Making stone cast:

o Pouring the impression with dental stone with vibrator to prevent air

bubbles.

3) Selecting the eye:

o This is performed in the 2nd appointment.

o It must match remaining eye.

o Left or right, size shape, color and blood vessels should be similar.


Mostafa Fayad

4) Carving clay pattern:

- Care should be taken in:

1- Restore symmetrically the wrinkles and opening of the eye lids.

2- Restore symmetrically the shape of inner and outer corners of the eye.

3- Distance from bridge of the nose to the Pupil of the remaining eye should

be equal.

4- The eye should be centrally located in the clay.

Plastic Eye Care Information

Yearly Checkups

evaluate the eye's fit and appearance

Polishing to removes protein and salt irritating deposits

Removal and Cleaning

All artificial eye wearers were told to remove and clean the prosthesis on a

regular basis to keeps the eye socket mildly irritated. Prosthesis cleaning is

typically performed once or twice a week

Eye Drops

Oily lubricant may be recommended in case of dry eye

Most patients get a new prosthesis every 3 to 5 years because even with excellent

maintenance, the tissues around the prosthesis can change and the artificial eye

can become scratched.


Mostafa Fayad

Orbital prosthesis

Implant retained orbital prosthesis

Implant fixtures placed in lateral portion of supraorbital rim


Mostafa Fayad

Auricular prosthesis

Anatomy and morphology

The ear or pinna is made up of

(1) a cartilaginous framework,

(2) fatty tissues, and

(3) an external covering of skin,

All of which impart to the ear its characteristic shape, color, and texture.

Causes of auricular defect

Form


Mostafa Fayad

Construction

Impression technique

Waxing up ,Try in & flasking

Delivery


Mostafa Fayad

Implant retained auricular prosthesis

Magnet-retained auricular prosthesis

Design and Fabrication of Auricular Prostheses by CAD/CAM

System

The mirrored image would serve as a basis for the ear prosthesis


Mostafa Fayad

Skin cell culture on an ear-shaped scaffold created by fused

deposition modelling Cai h. et al. Biomed Mater Eng. 2005

Tissue engineering, where cells attach and grow on a scaffold, has the potential to

produce replacement ears made from natural tissues and replace the need for

rubber prosthetic ears.

A three-dimensional image of the ear was used to manufacture ear-shaped

scaffolds from ABS (acrylonitrile/butadiene/styrene) plastic using FDM.

Human dermal fibroblasts were seeded on the scaffold (coated with fibronectin)

to attach and grow in culture medium in an incubator for two weeks.

Human keratinocytes were then seeded on to the fibroblast layer to attempt to

produce a more realistic skin covering.

The morphology of the cells were observed using scanning electron microscopy.

The results show that a realistic ear-shaped scaffold can be made using FDM. Human fibroblasts

were found to attach and grow. Human keratinocytes were successfully attached and grown on top of

the fibroblasts and this resulted in a skin covering over the scaffold.


Mostafa Fayad

Maxillofacial Prosthetic Management of a Patient with Hemifacial

Microsomia

Definition:

Hemifacial microsomia (HFM) is a disorder that results from the

underdevelopment of structures within the first and second branchial arches.

It is also the second most common craniofacial malformation, following cleft lip

and palate.

Due to a wide range of phenotypic expressions, a variety of names have been used

to describe HFM. They include Goldenhar syndrome, otomandibular dysostosis,

first and second branchial arch syndrome, oculoauriculovertebral sequence, lateral

facial dysplasia, and craniofacial microsomia.

Etiology

The etiology of HFM is complex. Teratogens, such as retinoic acid primidone and

thalidomide, as well as genetic factors have been implicated.

Both autosomal dominant and recessive inheritance patterns have been postulated

to explain familial cases of HFM.

Clinical manifestations

The clinical manifestations of HFM include a wide range of expressions. The

disorder is especially recognized by its facial asymmetry, due to the agenesis,

hypoplasia and/or displacement of the pinna. Maxillary, temporal, and malar

bones on the involved side are often reduced in size and flattened.

Furthermore, some patients may exhibit an underdeveloped mastoid region.

The eye on the side of the defect may be slightly lower than its counterpart,


Mostafa Fayad

The external ear of the involved side may range from distortion to complete

aplasia.

In some cases, bilateral anomalous pinnas and conduction deafness due to middle

ear abnormalities are observed.

Intraorally

patients with HFM may have hyperplastic or aplastic enamel,

significant delay of tooth development on the affected side,

Absence of the mandibular third molar and other teeth on the affected

side.

Chalky opacities in enamel are often found on the maxillary central and

lateral incisors on the affected side and serve as a distinguishing feature in

individuals with HFM.

cleft lip and/or palate,

hypoplasia of facial muscles,

Unilateral colobomas of the superior eyelid.

Management

craniofacial anomaly was treated using an implant-retained auricular

prosthesis for replacement of the pinna.


Mostafa Fayad

Craniofacial implants

Since the introduction of percutaneous endosseous implants for use with

bone conduction hearing aids in 1977, implants also have acquired an

important role in the prosthetic rehabilitation of patients with craniofacial

defects.

In 1983, Tjellstrom published results regarding osseointegrated

Craniofacial implants to retain auricular prostheses and also, bone-conducting

hearing aids.

In 1995, craniofacial osseointegrated implants were determined to be safe and

effective for this application by the United States Food and Drug Administration

(FDA).

Prerequisites of successful implant:

- The tissue bed should be free of infection.

- The tissue should be able to be closed over the implant without pressure.

- The tissue should have adequate blood supply.

Ideal characteristics of cranial implant:

1- It must be non carcinogenic:

o Physical rather than chemical factors are responsible for the change from

normal to tumor cells in the implanted animal.

o The implant should have a configuration which allows for the fibrosing of

the tissue through it and thereby disturbs cellular function less.

2- It must not cause excessive inflammation or foreign body reactions:

o A slight amount of inflammatory process is desired. This serves 2 functions

in implant patient:

1st : aids in fixating the implant in position.

2nd : it provides barriers to infection spreading the length of the prostheses.


Mostafa Fayad

3- It must be biostable:

o The ideal material should be biodegradable. But, it is not available so, the

biostable material is the one of choice.

4- It must be strong enough to withstand stresses:

o The stresses shouldn't cause implant fatigue and cause fracture.

5- It must be small enough to require a minimum tissue to cover:

o In both traumatic and surgical defects, the amount of tissue coverage has

been decreased or compromised.

6- It must be readily available and easy to fabricate.

7- It must be capable of being sterilized:

o This will prevent infection and subsequent complications.

Materials used for implant:

a) Tantalum:

o Contains: 18:8 stainless steel and chrome cobalt alloy.

o Comes in the form of sheets, wire, ribbon and mesh.

b) Chrome cobalt alloys:

o Well accepted by the body and have high rate of success.

c) Methyl methacrylate, Polyethylene and Silicone:

o manipulated in the dental laboratory.

d) Animal shells, Grounds, Coconut shells, Hard rubber, Plaster of Paris and

Gummed cork.

Position of craniofacial implants

o Implants in the mastoid process retain auricular prostheses.

o Orbital rim implants may anchor orbital prostheses

o Implants placed in malar bone and/or the anterior nasal

spine can be used to secure nasal prostheses.


Mostafa Fayad

Advantages of Implant retentive maxillofacial prosthesis

less wear and tear on the prosthesis, and daily cleaning is faster and easier.

Both of these factors contribute to extended life of the prosthesis.

Adhesive related skin irritation is eliminated and implants provide more reliable

retention of the prosthesis.

Precise placement of the prosthesis is assured as the retentive elements

automatically guide the prosthesis to its correct position.

less risk of discoloration through the use of adhesives

Osseointegration in irradiated bone

The adverse biological of ionizing radiation include

Alterations in the cellular components of bone, involving significant reductions in

the numbers of viable osteoblasts and osteocytes,

The development of areas of fatty degeneration within the bone marrow spaces.

The blood vessels undergo progressive endarteritis, hyalinization and fibrosis,

thus resulting in regional ischemia

Several papers have raised concerns by describing significantly shorter survival

rates when implants were placed in irradiated craniofacial bones, compared with

non-irradiated sites

Experimental and clinical findings indicate previous irradiation in therapeutic

doses is not an absolute contraindication for implant insertion.

It is recommended that some time elapse (minimally 1 year) before implant

placement in irradiated bone.

Hyperbaric oxygen (HBO) therapy can be used to improve the implant success

rate, by 38% according to the literature . However, in the mastoid region, HBO

therapy might not be necessary before placement of the implants unless the patient

has been irradiated with high radiation doses


Mostafa Fayad

It is possible to place craniofacial implants in patients with oncological lesions of

the head and neck during ablative surgery. especially when radiotherapy is

indicated, the possible advantages are the following:

1- Initial osseointegration takes place before irradiation and insertion of

implants in a compromised area can be avoided;

2- Earlier prosthetic rehabilitation; and

3- Surgical intervention in irradiated tissue is limited to second-stage surgery

However, there is general concern among head and neck surgeons and

radiotherapists that metal implants within the irradiated field may be cause

scattering, lead to overdose in the adjacent tissue over the course of radiation

therapy.

This could lead to three consequences:

1) Smaller irradiation dose reaching the tumor if it is situated behind the

implants;

2) Possible loss of osseointegration and implant failure because of the higher

irradiation dose; and

3) Increased risk of osteoradionecrosis developing in the bone adjacent to the

implant


Mostafa Fayad

Cranial prosthesis

Cranioplasty:

- The greatest progress in cranioplasty has been made in the development and

application of various plastic and non metallic alloplastic materials.

- Gold plates were inserted into skull defects. Then, inert metals were

used such as Vitallium, Ticonium, Tantalum and Stainless steel.

- The use of acrylic resin (Methyl methacrylate) is the most recent

development in this field.

Etiology of Cranial Defects

Trauma accounts for the majority of cranial defects

Infected bone flap

Excision of osteomas and other benign locally invasive lesions

Indications for cranioplasty:

1- Trauma.

2- Osteomyelitis of the skull.

3- Gun shoot wound.

4- Congenital defects.

5- Neoplasm of both cranial and

intracranial origin.

6- Epilepsy.

7- Pulsating and painful defects.

8- Danger of trauma at site of defect.

9- Deforming and unsightly defects.

10-Headache, pain and tenderness at

site of defect.

Precautions for cranioplasty:

1- Cranioplasty was not performed in presence of wound contamination or acute

chronic inflammation.

2- In one stage method of cranioplasty : methyl methacrylate has been almost

exclusively for both small and moderate large skull defects.

3- Split rib grafts have been used for large defects (Osteomyelitis).


Mostafa Fayad

Objective of Cranioplasty

For cosmetic reasons

For brain protection

Local discomfort at the site of the cranial defect

Methods of Cranioplasty

(1) Osteoplastic reconstruction

(2) Restoration with alloplastic implants.

Complications of cranioplasty:

1. Infection.

2. Instability of the prosthesis.

3. Erosion of the overlying skin.

4. C.S.F. leakage through dural laceration.

5. Epidural granuloma.

6. Hematoma.

7. Pneumothorax following rib removal.

8. Thermal damage to the surround tissue from the heat of polymerization of methyl

methacrylate.


Mostafa Fayad

Techniques of Cranial implant:

a) Technique of Methyl methacrylate cranial implant:

- Skin incision is designed to allow complete exposure of the

margins of the bone defect.

- Care must be taken to avoid lacerating the underlying dura

and brain.

- Periosteal elevator is used to fee the dura from the bone

edges.

- If the dura is full or tense, hyperventilation of the patient is

required to decrease intra-cranial pressure.

- The bone edges is freshened, rounded, and slightly beveled

with rongeurs. This also may be done using high speed drill

to provide a ledge which provide greater stability of the

plastic plate.

- When the preparation has been completed, a sterile liquid

monomer and powder polymer are mixed and takes 5 to 6

minutes to obtain doughy mass that can be conveniently molded.

- The material is placed over moistened cotton and shaped with fingers or a small

roller to a size approximating the defect and to the thickness of the surrounding

bone.

- A thin flange of acrylic around the periphery of the defect will provide increased

stability and also safety in that it prevents the implant from sinking into the

underlying tissue as a result of external pressure.

- The plate is then removed, and final hardening occurs outside the skull (Heat

generation).

- Many surgeons feel that a better fit is obtained if the plate isn't removed and final

hardening occurs in situ.


Mostafa Fayad

- Cooled Ringer's or normal saline irrigant should be continuously directed onto the

plate and surrounding tissue until the heat generated by polymerization has been

dissipated. (7:9 min.)

- All rongeur or dental burs are used to trim rough and sharp edges and to remove

excess material.

- For greater stability as well as for cosmetic purposes, wire may be used to bridge a

defect and may then be incorporated into the methyl methacrylate plate.

Advantages:

1. Excellent cosmetic results and easy to achieve.

2. Have same density and strength as bone.

3. Transparent to x-rays.

4. The material is inert and lacks the physical effects of metal plates as temperature

change and electric phenomena.


Mostafa Fayad

b) Split rip graft cranioplasty:

- Indicated for larger defects.

- Portions of the 9th or 10th ribs are generally used.

- After proper length of rib has been resected, the piece is split longitudinally with a

sharp thin chisel.

- The technique of exposing the skull defect and dura is the same as previous

technique.

- Part of the outer table is removed from the defect margins to form a ledge into

which the ends of the rib are inserted.

- Fixation is obtained with wire inserted through small holes drilled into the rib.

- The wound is closed in the usual manner.

- Head protection is recommended for several weeks until stabilization occurs.

Disadvantages:

1. The necessity of a separate incision.

2. Incomplete coverage of the defect.

3. There is a period required for stabilization.

c) Technique of Polyethylene Cranial Implant:

Advantages:

1. High density and high impact strength.

2. It is available in sheets and with proper compression molding.

3. Very strong and stress free product.

4. Inert.

5. Light in weight.

6. Radiolucent.

7. Easily trimmed at the time of surgery.

8. Cover large skull defects with good cosmetic results.


Mostafa Fayad

Steps of obtaining prostheses:

1. Impression taking with alginate impression material.

2. Modeling in stone.

3. Patterning with wax.

4. Flasking.

5. Compression molding at approximately 300° F.

6. Finishing.

7. Cold sterilization.

d) Technique of Tantalum Cranial Implant:

- To obtain the natural shape of the skull, it is important that

the head be shaved before the impression is made.

- The defect is palpated and the peripheral border is marked

with indelible pencil at a margin of approximately 1 to 2

cm from the penciled lines.

- The area is boxed in with boxing wax.

- The impression is made by applying irreversible hydrocolloid to the entire surface

of the boxed-in area.

- Pre-bent paper clips opened to an L shape are inserted in the impression material

for reinforcement.

- After setting of the irreversible hydrocolloid, quick setting plaster of Paris is added

for backing.

- When the plaster has set, the impression is gently removed from the skull and the

pencil line is reoutlined with indelible pencil.

- Dental stone is then poured slowly into the impression.

- Once the stone has set, the impression is separated from the moulage.

- At this stage, the prosthodontist study the moulage to determine whether an inlay

or onlay implant should be used.


Mostafa Fayad

- With an Inlay implant, a shoulder rest is prepared around the defect at the

periphery line 1mm deep to compensate for the tissue overlying the defect.

- The depressed area of the moulage is filled in with modeling clay or plaster to

bring the contour out to normal.

- One baseplate thickness of wax is applied to the pencil line as a pattern to cutout

the tantalum metal.

- The moulage is used as a die and after using separating medium, a counter die is

poured using a thick mix of stone.

- After setting, the 2 halves of the mold are separated and the tantalum pattern is

placed between the dies and the dies are inserted under press.

- After molding of the tantalum, it is peforated by the use of round burs size 5 : 8 to

allow the connective tissue to penetrate the implant and neutralize its physical

property.

- After making perforations, the implant is finished by rubber points, polished,

scrubbed, and immersed in nitric acid to eliminate contamination.

- The tissue bed is prepared in the same manner as described for methyl

methacrylate.

- The sterilized perforated tantalum implant is then seated over the cranial defect

and fixed with 4 to 6 stainless steel wires to the surrounding skull.

- The wound is closed in layers as usual manner.

Disadvantages associated with metal cranial implants.

Their high thermal conductivity may precipitate headaches and other neurological

symptoms.

Their electrical conductivity precludes accurate interpretation of

electroencephalograms.

Some metals, are radiopaque and may prevent interpretation of routine

radiographic studies.


Mostafa Fayad

Perforated Tantalum Implants for Reconstruction of Facial Bones:

- Used for reconstructing other defected facial bones, such as the infraorbital bone,

the zygomatic orbital malar bone, the symphysis and associated mandibular

defects.

- Used in case of T.M.J. ankylosis after accident.

Silicone Implant for Reconstruction of Facial Bones:

- Used for reconstruction of the dorsum of the nose, the floor of the orbit, the malar

bone, the forehead, and the mandibular ridge.

- Used to build out the retrognathic chin and to build the helix of the ear.

- The silicone implant material must be perforated to provide tissue growth which

will retain the prosthesis in place.


Mostafa Fayad

Stereolithographic Model

Three-dimensional (3-D) modeling by deposition of U.V light cure epoxy resin

Rapid prototyping technology

The use of computer-controlled milling process to

manufacture models from blocks of polyurethane foam

STEREOLITHOGRAPHY

Advantages.

Anatomically 3 dimensionally accurate.

Disadvantages.

Expensive to have built. Poor tooth detail.


Mostafa Fayad

Coloration of maxillofacial prosthesis

RULES

The patient must always be present for the color match

Accurate color match is the final determinant in creating

an acceptable prosthesis

Realistic cosmetic matching depends on the combination of in-depth intrinsic and

extrinsic colorations

Depth of color and translucency achieved through intrinsic technique

Surface detail (b.v., freckles and moles) achieved through extrinsic technique

The extrinsic coloration uses a medical-grade adhesive combined with xylene and

earth pigments,

Trial and error

Obtaining color match

a) Traditional trial & error method

Intrinsic color technique

Intrinsic coloration composed of base shade and localized color.

Base color : represent the majority of the tissue color

Localized color: as Tip of the nose , Outer concha & ear lobule

The technique of applying the localized color must be in layering method to produce

good depth of color with gradual change from base color to localized color


Mostafa Fayad

The application of localized color must be done firstly then the base color

Obtaining the correct base shade complicated by

1. Incorporation of air into the silicone during mixing

2. Thickness of the mix

3. Background color of mixing container

Consideration

Color match must be done in a room with neutral gray walls

Avoid hard demarcation of color layers

Use small amount of clear elastomer just below the surface of the prosthesis to create translucent pigmentation

The edges of the prosthesis must blend into the surrounding tissue with the same color balance

Extrinsic coloring must be carried out at the fitting appointment and should be kept to a minimum

Extrinsic color technique

It used to compensate slight color imbalance

Extrinsic color used to apply freckle, mole and capillaries

After applying of extrinsic coloration a thin layer of medical adhesive must be applied over the entire surface and tamped with wet gauze to attain surface texture.


Mostafa Fayad

b) Computerized color formulation

This done by computing a pigment formula with color formulation software that matches a measured skin color

Advantages

1. Reduced clinical time

2. The formula can be mixed repeatedly and accurately

3. Metamerism is minimized since the formula obtained under three different illumination sources .

4. Translucency can be controlled as pigment loading done acc. to the color formulation software

Spectrophotometer &colorimeter

Spectrophotometers use an optical mechanism to break down light

entering the instrument into it's component parts and measuring

them in an objective manner

Colorimeter consists of sensor and simple data processor, it is less

complex than spectrophotometer And used for comparison of

similar colors and adjustment of small color difference


Mostafa Fayad

Interim extraoral prosthesis

An interim extraoral prosthesis used for the rehabilitation of a patient treated for

osteoradionecrosis of the mandible

Speech

Mostafa Fayad 1

Speech

Speech is a learned process that used the anatomic structures designed primarily

for respiration and deglutition. There are no organs of speech per se. As a learned

process, speech develops over an extended period.

Components of speech:

The speech can be divided into the following components:

Respiration : During respiration, inhalation and exhalation are approximately equal in

duration and the airflow is regular and repetitive. During speech, the inhalation is

shortened and the exhalation phase is prolonged and is not repetitive. Prolongation of

exhalation is achieved by the valve mechanisms along the laryngeal, pharyngeal and oral

components of the respiratory truct. These valves impede the expired air and help to

create speech signals. If the vital capacity of the lungs is compromised, as in emphysema,

speech will be perceived as breathy. The reduced volume and pressure of the expired air

cause poor projection of voice.

Phonation :Speech requires a multitude of position, varying tensions, vibratory cycles,

and intricate coordination of the vocal folds with other structures. If the focal folds are

partially or completely closed, they impede the expired air. With the proper degree of

tension and pressure, the vocal folds may vibrated and thus impart phonation. The tension

and position of the vocal folds will determine the pitch of the phonated sound. If the

larynx is resected the patient must learn to use the esophagus or a substitute mechanical

device (electrolarynx) as an alternative phonating system.

Resonation: The sounds produced at the level of the vocal folds are augmented and

modified by the chambers above the level of the glottis. The pharynx, the oral cavity, and

the nasal cavity are providing tonal quality and act as resonating chamber by amplifying

voice. If palatopharyngeal closure is compromised, or if the structureal integrity or the

Speech

Mostafa Fayad 2

size of the oral, pharyngeal or nasal cavities has been altered, a compromised voice

quality will occur.

Articulation: The amplified, resonated sound is formulated into meaningful speech by

the articulators, i.e., by changing the special relationship of the tongue, the lips, the

cheeks, the teeth and the palate to each other. The tongue is the single most important

articulator of speech because of its ability to changes in movement and shape.

Neural integration: Speech in integrated by the central nervous system. At least 17000

different motor patterns are required during speech. A cerebrovascular accident may

compromise the ability of the patient to formulate meaningful speech, even though all

structures used to produce speech are anatomically normal.

The ability to hear sounds (Audition) : Hearing permits reception and interpretation of

acoustic signals and allows the speaker to monitor and control speech output.

Compromised hearing can preclude accurate feedback and affect speech.

Speech and Maxillofacial Prosthetics

resonance and articulation are distorted by cleft lip and cleft palate. These two

components of speech are the readily influenced by maxillofacial prosthodontic

rehabilitation.

A-Patients with cleft palate exhibit excessive nasal resonance because the inadequacy of

the velopharyngeal closure. This results in nasal sounds (hypernasality).

B- The sounds not affected by palatal clefts are the vowels (A,I, E,O and U) and nasal

consonants (M,N and NG).

C- The articulation of the other consonants is affected in varying degrees, depending on

the degree of oral pressure required for each sound. These sounds are deprived of their

normal explosive character (e.g. P and K) and give the voice a typical hollow nasal

quality.

Speech

Mostafa Fayad 3

The Techniques of Normal Speech

The initial sound of speech is produced in the larynx and travels as a vibrating air

stream either through the mouth where it is articulated by the tongue, lips, palate and

teeth, or through the nose where the nasal cavities and associated sinuses produce a nasal

resonance. The rapid and accurate positioning of the soft palate is essential for the

production of the correct sound. When speaking, all sounds except for those of m, n and

ng, the soft palate is raised preventing all nasal escape of air which is thus wholly

directed through the mouth where it is modulated in one of three ways.

1-The vowel sounds

The vowel sounds A,E,I,O,U are formed by a continuous air flow escaped through the

mouth. The shape of which is altered for the various vowels by raising or lowering the

tongue and by altering the shape of the exit through the lips. The air was escaped through

the mouth in the form of a single chamber for the A , O , U sounds and a duple chamber

for the I and E sounds. The division occurring through the dorsum of the tongue

touching the anterior part of the soft palate.

2-Stopped consonants:

The stopped consonants are produced by first of all stopping the air stream momentarely

and then allowing it to escape through a cavity shaped to produce the sound in question.

Examples of these are

B and P sounds (labials). The air streams is stopped momentarily by closure of the lips

and then released explosively when the lips are suddenly parted .

T and D sounds (linguodentals); The stop is made by the tip of the tongue being

pressed against the palatal surfaces of the upper front teeth.

G and K sounds (lingo-palatals); The momentary stop is made by the back of the tongue

being pressed hard against the hard palate.

Speech

Mostafa Fayad 4

The first phase of the “B” sound. The

lips are closed and therefore the

airstream is stopped when it reaches

them and is held there under pressure,

the second phase of “B:” sound. The

lips are suddenly opened and the

stopped airstream is released

producing the “B” sound.

For the F and D sounds, the stop is made

with tip of tongue and the palatal surface

of the upper anterior teeth.

The stop is made with tongue and

palate for the “G” sound.

3-The fricatives consonants sounds

Some sounds are termed “fricatives” to describe the friction. Like way in which they are

produced. The fricatives S , Z and C sounds; are produced by allowing the air stream

under pressure from the lungs to escape through a finely adjusted slit formed between the

dorsum of the tongue and the palate.

The M , N and NG sounds; these nasal consonants are the only sounds produced with the

soft palate lowered, allowing the air stream to escape through the nose. In the M sound

the air take the nasal route only. In the N and Ng sounds the escape is partially through

the nose and partially through the mouth.

Generally, the oral cavity and the sinus act as resonant chambers, and the muscles of the

abdomen

Speech

Mostafa Fayad 5

The factors in denture construction affecting phonation

The vowel sounds:

The tip of the tongue in all vowel sounds lies on the floor of the mouth either in

contact with or close to the lingual surfaces of the lower anterior teeth and gums. The

application of this in denture construction is that the lower anterior teeth should not be set

lingual to the alveolar ridge so that they do not impede the tongue positioning for these

sounds;.

Since the vowels E and I necessitate contact between the tongue and soft palate,

the upper denture base must be kept thin, and the posterior border should be tapered and

merge into the soft tissue in order to avoid irritating the dorsum of the tongue, which

might occur if this surface of the denture was allowed to remain thick and square-ended.

The consonant sounds

These sounds may be classified thus

1- Labials: Formed by the lips (e.g. B, P, M).

The anterior teeth and the denture flange must support the lips for these sounds.

2- Labiodentals: Formed by the lips and teeth (e.g. F, V, Ph).

These sounds are produced by the air stream being stopped and explosively released

when the wet-dry line of the vermilion border of the lower lip breaks contact with the

incisal edge of the upper anterior teeth (Fig 5-4). If the occlusal plane is set either too

high or too low or if the anterior teeth are placed too far palatally and fail to provide

proper lip support, difficulty in pronouncing these sounds may occur.

3- Linguodentals: Formed by the tongue and teeth (e.g. Th).

Speech

Mostafa Fayad 6

This sound (as in “thin” , “then”) is the result of air flow restricted by the tongue against

the incisal edge of upper and/or lower incisors. The proper adjustment of the occlusal

plane and the proper positioning of the anterior teeth are necessary for these sounds.

4 -Linguopalatals: Formed by the tongue and palate.

The palate serves two speech functions, resonation and articulation. In articulation,

it directs the air stream. The linguopalatals sounds can be divided according to the part of

palate that make contact with the tongue during speech.

a- Tongue and anterior portion of the hard palate (e.g. S, C “soft”, Z, D, T, R, L).

With T and D, the tongue makes firm contact with the anterior part of the hard

palate, and suddenly drawn downwards, producing an explosive sound. When producing

the S , C “soft”, Z , R and L sounds, contact occurs between the tongue and the most

anterior part of the hard palate, including the lingual surface of the upper and lower

incisors, any thickening of the denture base in this region may cause incorrect formation

of these sounds.

The lower lip is brought into contact with the incisal edges of the upper

anterior teeth during production of the F, V and Ph sounds.

In case of S , C “soft” and Z sounds, a slit-like channel is formed between the

tongue and the palate through which the air hisses. If this channel is obstructed by

thickening the anterior part of the upper denture covering the hard palate, by placing the

anterior teeth too far back, or by lack of near contact of the upper and lower incisors, a

noticeable lisping may be produced. However , if the channel is too narrow, due to

Speech

Mostafa Fayad 7

cramped tongue, too narrow dental arch, or placing the anterior teeth too far anteriorly

whistling will result.

The procedure for correcting whistling is to thicken the center of the palate so that

the tongue does not have to extend up, so far into the narrow palatal vault. This allows

the escape way, for air to be broad and thin.

A lisp with denture can be corrected by reversing the procedure and providing a

narrow concentrated airway for the S sound.

The correct positioning of the anterior teeth (antroposteriorly) important for

proper sounds of S, C (soft), Z, R, and L and for preventing both lisping and whistling.

b- Tongue and portion of the hard palate posterior to that of (a) (e.g. J, CH, SH, L, R)

Faulty phonation of these consonants sounds may be results from thickening of

this part of the denture base covering the hard palate.

With the C ”soft”, S, Z, CH and J sounds the teeth come very close together; if the

vertical dimension is excessive, a clicking teeth will results with these sounds.

c- Tongue and soft palate (e.g. C ”hard”, k, G, NG).

Difficulty in pronouncing these sounds results if the posterior border of the upper denture

is thick and does not merge into the soft tissues.

5- Nasal (e.g. M, N, NG).

In these consonants sounds the air stream is allowed to escape into the nasal cavity.

A careful consideration should be given to the following aspects of denture

construction to prevent or reduce the speech defects:

1- Denture thickness and peripheral outline

Speech

Mostafa Fayad 8

unduly thick denture bases may cause :

loss of tongue

loss of tone

incorrect phonation.

- The periphery of the denture must not be overextended .

- The thickness of the denture base covering the palate should not be thick.

- The artificial ragae should not be over-pronounced.

2- Vertical dimension

- high vertical dimension cause clicking teeth with Ch and J sounds

construct the denture with proper vertical dimension.

3- The occlusal plane

If the occlusal plane is set too high the correct positioning of the lower lip may be

difficult. If the plane is too law, the lip will overlap the labial surfaces of the upper

anterior teeth to a greater extent than is required for normal phonation and the F, V and

Ph sounds might be affected.

4- The anteroposterior postion of the incisors

The labiopalatal position of the upper anterior teeth is important for the correct formation

of the labiodental F,V and Ph and some palatolinguals S, C “soft” and Z, lisping with

result if the anterior teeth are placed too far palatally.

5- The post-dam area

Errors of construction in this region involve the vowels I and E and some

palatolingual consonants K,NG, G and C “had”.

Speech

Mostafa Fayad 9

If the denture base was made thick in the post-dam area, or the edge finished

square instead of tapering, the dorsum of the tongue will be irritated, impeding speech

and nausea may occurs.

Indirectly the post-dam seal influences phonation by increase the denture

retention, because in case of loss upper enture the patient tries to suck maxillary denture

into position, using tongue to hold it, hence, mouth does not open widely, speech

becomes muffeld.

6- Width of dental arch

The artificial teeth should be placed in the neutral zone.

If the arch form of the denture is too narrow the tongue will be cramped, thus

affecting the size and shape of the air channel and the lateral margins of the tongue make

contact with the palatal surface of the upper posterior teeth. These results in faulty

phonation of some consonants as T, D, S, M, N, K, G, and H.

7- Relationship of the upper anterior to the lower anterior teeth

The consonants S, Ch, J, and Z requires near contact of the upper and lower

incisors so that the air stream is allowed to escape through a slight opening between the

teeth.

In abnormal protrusive and retrusive jaw relationships, some difficulty may be

experienced in the formation of these sounds, and the anteroposterior adjustment of the

upper and lower anterior teeth become necessary.

Some phonatic complaints associated with prosthesis

1- Loss of tone and incorrect phonation

Causes: - Decrease of air volume and loss of tongue room resulting from too

narrow dental arch.

Speech

Mostafa Fayad 10

- Unduly thick denture bases (especially this part covering the palate).

- Overextended denture and periphery.

Treatment: - Broaden and widen arch form.

- Use narrow teeth.

- Reduce the thickness of the denture base.

- Adjust denture periphery.

2 -Drooling

Causes: - Arch form too constricted.

- Reduced vertical dimension.

- Poor muscle support.

Treatment: - Widen and boarden the arch form

- Restore proper vertical dimension.

- Teeth should be placed to support soft tissue more firmly.

3- Limited jaw mobility and low intensity of speech production:

Causes: - Denture looseness; patient tries to suck maxillary denture into position,

using tongue to hold it, hence, mouth does not open widely, speech

becomes muffled, and jaws move little.

Treatment: - Check dentures for lack of adaptation, improper border extensions,

insufficient posterior palatal seal and deflective occlusal contacts.

Then correct the defect.

Speech

Mostafa Fayad 11

4- Phonetic Sh instead of S

Treatment: - Have a slight vertical overlap.

- Increase vertical dimension.

-Set lower so incisal edges can approximate maxillary teeth to

within 1 mm.

5-Clicking sound

causes: - High vertical dimension.

- Use of porcelain teeth.

- Poor retention of the denture.

Treatment: - Decrease the vertical dimention.

- Use risen teeth.

- Treat the cause of poor retention.

6-Lisping and whistling:

mensioned before.

Retention of Maxillofacial Prosthesis

I-Retention of Intraoral Prostheses

A-Anatomic Retention:

This includes the use of both hard and soft tissues (teeth, mucosal and bony

tissues). Large alveolar ridge and high palatal vaults generally provide more

retention than flatter ridges. Anatomic undercut areas play an important role in

retention of prosthesis. The success of intraoral retention relates to the size and

location of the defect and the type of the mouth, dentulous or edentulous e.g.

For edentulous patient with any palatal perforation, retention in the classical sense

of complete denture is impossible. Even in dentulous patient with resected

maxilla, clasping only will not give better results. The movement of the prosthesis

will make stress on the abutment teeth and may result in loss of the abutment. So

more than one method of retention should be used.

B-Mechanical Retention: (Temporary or Permanent)

Temporary Mechanical Retention:

1- A stainless steel wrought wire of 18-gauge size can be quickly

adapted to a cast of the remaining teeth to retain the temporary

prosthesis during the healing period. Preformed stainless steel wire

clasps include Adams, Akers, or Hawley labial wires may be used

Preformed stainless steel bands or crowns with prewelded brackets can be adapted to

increase retentive form of a mutilated or conical tooth.

2- wiring the denture to infraorbital or zygomatic bones to obturate a

maxillary defect is recommended for edentulous patient..

Retention of prosthesis: Upper through circumzygomatic wiring

and lower through circummandibular wiring.

Permanent Mechanical Retention:

1-Cast clasps

The most common method for retaining a prosthesis is the use

of cast metal clasps. There are many different types of cast

metal clasps e.g. cast circumferential clasp, ring clasp and I-Bar

clasp .

2-Prefabricated precision attachments:

These attachments can be placed into cast crowns for the best esthetic and mechanical

retention.

3-Semiprecision attachments, custom made

This attachments are formed in the wax pattern, using a specially shaped mandrel

mounted on the parallelometer .

4-Snap-on attachment

A Baker bar or Anderson bar is the rod

connecting two crowns of abutment, and the

clip engages this rod.

5-Overdentures

Improved retention may be obtained by one of the several attachment devices or by lining

the overdenture with one of the resilient denture liners to utilize available tooth

undercuts.

6-Overlay (Telescoping) Crown and Thimble Crown

This type is used when an overlay denture is planned or an

extremely malposed tooth is needed for stability.

It is also indicated when a major change in the vertical or

centric dimension occur , as in cleft lip-cleft palate, and

prognathic mandibles.

Fig. (A) Thimble crowns cemented on prognathic patient,

(B) Telescoping crowns imbedded in the denture.

7-Swing-lock attachments

Swing-lock partial denture design using long flexible

arm to engage anterior and posterior abutment teeth.

The swing-lock design should not be used at all

unless splinting of the posterior teeth is first

accomplished.

8- Retaining buccal flange

Retaining buccal flange engaging both tooth and tissue undercuts

9-Using the undercuts in the defect

Soft silicone material is used to engage the undercuts in

the defect more aggressively.

10-Engagement of the skin graft and scar band formed at the skin graft-mucosal

junction .

Junction of oral mucosa and skin graft lining can give accessory retention and should be

used whenever possible.

(A) Junction of oral mucosa and skin graft, (B) Lateral defect space traced in compound showing

construction of scar band and extension to lateral shelf created by tumor removal.

11-Magnets

Small steel magnets are embedded beneath the molar and premolar teeth of upper and

lower dentures and arranged with similar poles opposite each other. At least two magnets

are required for the lower denture and four magnets for the upper denture.

This effective method of retention may be useful in cases of hemi-maxillectomy, or

extremely atrophied ridges. The use of magnets in two piece prosthesis is advocated.

12-Using of springs

The opposing arch can be used to assist in the retention of the maxillary prosthesis by

attaching a spiral spring to the prosthesis in the premolar region. These spiral springs are

made of coiled stainless steel or gold-plated base metal and have their ends attached to

swivels in the premolar areas on both sides of upper and lower dentures.

(A) Spring - retained prosthesis, (B) Spring - retained denture with obturator.

Nylon springs of continental origin are available and have the advantage of being thin

and not collecting food .

Their life is limited to about six months, and the method of their attachment to the

denture, which is a nylon ball and socket joint, is not very efficient. If this were improved

they would be very satisfactory.

The disadvantages of nylon springs are:

1-The constant pressure may cause excessive alveolar absorption

2-The mucous membrane may not tolerate the constant pressure.

3-The inner surfaces of the cheeks may become sore from frictional contact with the springs.

4-Lateral movements are extremely restricted.

5-Collecting foods and become unhygienic.

13-Implants in the intact side

Improved retention may be obtained by one of the several attachment which can be used

with the implants.

14-Adhesives (fixatives), Prosthetic Adhesives, 1970

These materials improve fit, comfort and retention of the prosthesis by producing a high

viscous layer between the denture and its supporting tissues.

This material is necessary to aid retention in the following cases:

a- Large surgical wound.

b- Flat palate.

c- Nonexistent maxillary tuberosities.

d- Missing of soft tissue undercuts in the area of surgery.

e- Diminished salivary flow due to pre-and postredication therapy.

f- loss immediate upper denture due to alveolar absorption .

The requirements of adhesives are

1. Highly adherent;

2. Nontoxic—that is, nonirritating to the tissues;

3. Elastic at the point of contact to the skin;

4. Non injurious to the prosthesis;

5. Highly durable;

6. Easily cleansed from the surface of the prosthesis as well as from the soft tissue involved.

Disadvantages

1-It gives a temporary retention .

2-It has an unpleasant feel when pressed out from beneath the denture.

3-It is of little use for retaining lower dentures.

4-Its constant use may cause constipation.

The troubles with adhesive

Difficult to clean

They collect dirt and are unhygienic

Unreliable (swimming, sweating or greasy skin)

Awkward to position correctly

The application of the adhesive may be messy and time-

consuming.

The edges of the prosthesis must often be thickened or reinforced with fabric to

resist tearing that may occur as the adhesive is cleaned from the prosthesis on a

daily basis.

The adhesive may cause skin irritation,

Retention by the skin adhesive may be unreliable, especially if the prosthesis is large, the

weather humid, or if the patient has oily skin. Proper positioning of the prosthesis is

difficult in the absence of key anatomical landmarks; especially if the patient has

compromised manual dexterity or visual acuity.

II-Retention of Extra-oral Prosthesis:

A-Anatomic retention

The dynamic extra-oral retention depends on many factors. These factors are

related to the size and location of the defect, tissue mobility, undercuts and the

wright of the prosthetic material.

Both hard and soft tissues should be used; The hard tissue act as a base and

provide a better seal of the prosthesis with the use of adhesive. While the soft

tissues are more troublesome because of their flexibility, mobility, lack of support,

low resistance to displacement.

B-Mechanical retention

In cases of large defects involving half of the face additional retention is needed

beside the use of adhesives.

The use of eye glasses with elastic strap as an indirect mechanical retention to

retain the prosthesis.

The magnets may be imbedded in a nasal or orbital prosthesis to retain it to the

maxillary obturator.

C-Adhesives

The adhesives aid retention, marginal seal, border adaptation, and recures the

prosthesis against accidental dislodgment. Generally, each material provides its

own adhesive according to its physical and chemical properties.

D- Combination of anatomic, mechanical and adhesive retention:

In case of large facial replacements all available means of retention should be used

to obtain better stability and retention.

Maxillofacial prosthetics theory and practice 2011

Health & Medicine

Transcript of Maxillofacial prosthetics theory and practice 2011