Guided by: Dr. Sunil Sharma

PRESENTERDr. Ashish Soni

C O N T E N T S INTRODUCTION

DEFINITIONS

ORDER OF FREQUENCY OF IMPACTED TEETH ETIOLOGY PROBLEMS DUE TO RETAINED IMPACTED TEETH INDICATIONS FOR REMOVAL

CONTRAINDICATIONS FOR REMOVAL

IMPACTED 3RD MOLARS• SURGICAL ANATOMY• CLASSIFICATION• PRE-OP ASSESSMENT

PRE-OP MANAGEMENT OF IMPACTED TEETH SURGICAL TECHNIQUES

SURGICAL SIDE-EFFECTS AND COMPLICATIONS

REFERENCES

D E F I N I T I O N S IM P A C T E D T O O T H : A tooth which is completely or partially unerupted

and is positioned against another tooth, bone or soft tissue so that its further eruption is unlikely, described according to its anatomic position. (Archer)

M A L P O S ED T O O T H : A tooth, unerupted or erupted, which is in an abnormal position in the maxilla or mandible.

U N E R U P T E D T O O T H : A tooth not having perforated the oral mucosa. A N K Y L O S E D T O O T H : When the cementum of the tooth is fused to the

alveolar bone and there is no periodontal ligament in between, a tooth is considered to be ankylosed.

S U B M E R G E D T O O T H : A decidous tooth which is ankylosed , prevents

their exfoliation and subsequent replacement by permanent tooth. After the adjacent permanent tooth have erupted, the ankylosed tooth appears to have submerged below the level of other teeth.

O R D E R O F F R E Q U E N C Y O F I M P A C T E D T E E T H

Maxillary 3rd Ms Mandibular 3rd Ms Maxillary cuspids Mandibular bicuspids Mandibular cuspids Maxillary bicuspids Maxillary central incisors Maxillary lateral incisors

A c c o r d i n g t o A r c h er

ETIOLOGY

TH E O R I E S O F I M P A C T I O N

According to DURBECK, causes can be discussed under 5 separate theories:

Orthodontic theory Phylogenic theory Mendelian theory Pathological theory Endocrinal theory

O r t h o d o n t i c t h e o r yThe normal growth of the jaws and movement of teeth is in a forward

direction and anything interfering with such development will cause an impaction of teeth.

Dense bone and many pathologic conditions like acute infections, fever, severe trauma ,malocclusion ,inflammation of the periodontal membrane etc which can cause increased bone density - retards such forward growth of the jaws

Constant mouth breathing - contracted arches. Thus leaving insufficient room for erupting M3.

Early loss of deciduous teeth - arrested development of teeth, resulting in impactions.

P h y l o g e n i c t h e o r y Nature tries to eliminate that what is not used, and our civilization

with its changing nutritional habits has practically eliminated the human need for large powerful jaws.

As a result, the size of jaws has decreased - abnormal position of M3 leading to impaction

M e n d e l i a n t h e o r y Heredity – such as transmission of small jaws from parent and large

teeth from the other parent– may be an important etiologic factor in impactions

P a t h o l o g i c a l t h e o r y Chronic infections affecting an individual may bring the

condensation of osseous tissue further preventing the growth and

development of the jaws.

E nd o c r i na l t h e o r y Increase or decrease in growth hormone secretion may affect the

size of the jaws

LOC A L C AUSE S

B er g er lists the following local causes of impaction : Irregularity in the position and presence of an adjacent

tooth.

Density of the overlying or surrounding bone.

Long – continued chronic inflammation with resultant increase in density of the overlying mucous membrane.

Lack of space due to underdeveloped jaws. Unduly long retention of the primary teeth. Premature loss of the primary teeth. Acquired diseases, such as necrosis due to infection or

abscesses and inflammatory changes in the bone due to exanthematous diseases in children.

S Y S TE M I C C A U S E S Prenatal causes

Heredity

Postnatal causes Rickets Anemia Congenital syphilis Endocrine dysfunctions Malnutrition

Rare conditions Cleidocranial dysostosis Oxycephaly Achondroplasia Cleft palate

PROBLEMS DUE TO RETAINED IMPACTED TEETH

Fascial space infections

Infections arising from M3 may be spread through various tissue planes:

Pterygomandibular space Lateral pharyngeal space Retropharyngeal space

RISK OF CYST & TUMOR DEVELOPMENT

Most common age : 20- 25 years. Incidence of dentigerous cyst- 1.6% (KEITH,1973) Incidence of cyst formation-2.31%(Guven et al,2000) Incidence of ameloblastoma – 0.14- 2 %(Shear,1978)

Dental caries Pain Risk of mandibular fracture: Trismus. Chronic cheek biting. Resorption of adjacent tooth. Other complications :

Ears - Ringing, singing or buzzing sound Eye - dimness of vision, blindness, iritis, pain simulating that

of glaucoma

I N D I C A T I O N S F O R R E MO V A L Any symptomatic wisdom tooth Grossly decayed 3rd molars Periodontal disease Dentigerous cyst formation or other related oral pathology External resorption of 3rd molar or of 2nd molar Infection. Non restorable dental caries. Interference with orthodontic treatment. Presence of impacted tooth in the line of jaw fracture. Persistent pain of unknown origin. Pre-irradiation. Resorption of adjacent teeth. Proceeding fabrication of adjacent restorative crowns and dentures. Removal of 3rd molar prior to orthognathic surgery

Contraindications for removal of impacted teeth Possible Damage to Adjacent Structures

If the removal of an asymptomatic impaction is likely to result in the loss of adjacent teeth, damage to the vital structures like neurovascular bundle, the tooth should be left in place.

Compromised Physical Status One of the most significant factors to be considered when

removing of an impacted tooth is the patient's physical condition and life expectancy. Surgical removal is contra indicated if the patient is not fit to undergo minor oral surgical procedure.

Prosthetic consideration Sometimes, partially erupted tooth has to be retained

since such a tooth could be utilized as an abutment for a fixed partial denture.

Availability of adequate space: If adequate space is available for the eruption of the

unerupted tooth, it is better to retain it. Socioeconomic reasons:

The patient may not be willing for removal due to fear or socioeconomic reasons.

Loc al fac to rs Radiotherapy Teeth in close proximity to tumour Acute gingivitis

Sy s t emi c f ac tor s Uncontrolled diabetes Pregnancy Underlying bleeding disorders Cardiac conditions Patients on anticoagulants,steroids,etc.

I MP A C T E D MA N D I B U L A R 3 r d MO L A R S

Surgical anatomy The main external osseous features of the

mandibular first and second molar region are the very thick roll of convex lateral bone

extending from the crest of the alveolus to the base of the mandible and

On the medial (lingual) aspect the alveolar process area declines in height as it passes posteriorly, and it is convex with a thick roll of cortical bone.

The mylohyoid ridge continues posteriorly in an upward sweep toward the third molar region. Below the mylohyoid ridge there is usually a concavity in the medial aspect of the mandible, the submandibular fossa. However, normal variations of the anatomy below the mylohyoid ridge include the area’s being convex rather than concave.

The Retromolar Triangle

Behind the third molar is a depressed roughened area on the upper surface of the mandible which is bounded by the lingual and buccal crests of the alveolar ridge this is the retromolar triangle.

Lying lateral to the retromolar triangle is a shallow, hollow depression, the retromolar fossa, which is bounded by the anterior border of the ascending ramus and the temporal crest.

The retromolar triangle is the site for initial surgical procedures to remove the usual impacted mandibular third molars.

Retromolar canal and foramen It is a rare anatomic variation, found In the

retromolar triangle through which emerges branches of the mandibular vessels

According to Schejtman, Devoto and Arias (1967), are distributed over the temporalis tendon, buccinator and adjacent alveolus.

Contents of this canal originates from mandibular neurovascular bundle.

Anderson et al. (1991) – innervate and supply temporalis M, part of buccinator M, retromolar trigone.

Although these are small vessels a brisk hemorrhage can occur during the surgical exposure of the third molar region if the distal incision is carried up the ramus and not taken laterally towards the cheek.

Inferior Alveolar canal

The inferior alveolar canal may be present as a single cortical bony tube that can be in various locations lateral to, medial to, inferior to, and, possibly, through the roots of the mandibular teeth.

Instead of a single canal, multiple tubes may be present, carrying nerves and vessels to single teeth or to groups of teeth and to the mental foramen.

Various routes and patterns of IAN.

Lingual Nerve The lingual nerve may be hidden beneath or in the mucosa lateral to the

location of a mandibular third molar near the crest in an abnormal, superior position.

V a r i a t i o n s i n l i n g u a l n er v e : f r o m t h e c r es t o f t h e l i n g u a l b o n e t o t h e f l o o r o f t h e m o u t h

In regard to the horizontal & vertical In regard to the horizontal & vertical distance, distance, Kiesselbach and Chamberlain(1984Kiesselbach and Chamberlain(1984) ) found that the lingual nerve was found that the lingual nerve was 0.58mm H & 2.26mm V medial to the 0.58mm H & 2.26mm V medial to the lingual plate.lingual plate. Pogrel et al’s (2000)-Pogrel et al’s (2000)- 3.45mm H & 3.45mm H & 3.01mm V . 3.01mm V . Miloro et al’s(1995)Miloro et al’s(1995) measurement measurement 2.53mm H & 2.75mm V.2.53mm H & 2.75mm V.

C l a s si f i c a t i o n su g g e st e d b y P e l l & G r e g o r y ( 1 9 3 3 ) , w hi c h i nc l u d e s p o r t i o n o f G e o r g e B W i nt e r ’ s c la s s i f i c a t i o n( 1 9 2 6 ) :

A . Av ai la bi li t y of s p ac e b etw ee n 2 n d mola r a nd ramu s of t he mandi b le (h or iz ontal p la ne) :  Class I

There is sufficient space between the ramus of the mandible & the distal side of the second molar for the accommodation of the mesiodistal diameter of the crown of the third molar.

Class II

The space between the ramus of the mandible & the distal side of the second molar is less than the mesiodistal diameter of the crown of the third molar.

Class IIIComplete or most of the third molar is located within the ramus.

B . R elati ve dep t h of t h e 3 rd mol ar in b one ( v ert ic al p lane) :P o s i t i o n A

T h e h i g h e s t p o r t i o n o f t h e t o o t h i s o n a le ve l w i t h o r a b o v e t h e o c c l u s a l p l a n e . P o s i t i o n BT h e h i g h e s t p o r t i o n o f t h e t o o t h i s b e l o w t h e o c c l u s a l p l a n e , b u t a b o v e t h e c e r v i c a l l i n e o f t h e s e c o nd m o l a r . P o s i t i o n C

T h e h i g h e s t p o r t i o n o f t h e t o o t h i s b e lo w t h e c e r v i c a l l i ne o f t h e s e c o nd m o l a r .

C . Lo n g a xi s of the i mpac te d t o ot h i n re la t i o n t o t he l on g axi s o f the 2 nd mol a r (a n gu l at i on ; Wi n t er ’ s cl assi f i ca t io n ) :

1 .           V e rt i ca l .2.           H or i zo n t al .3 .           In ver t ed.4.           Me si o an gu l ar .5 .           Di st o an g ul ar .6.           B uc coa n gu l ar .7 .           Li n g uo a n gul a r .

A simple method of determining the type of impaction involves comparing the distance between the roots of 3rd and 2nd molars , with the distance between the roots of the 2nd and 1st molars .

G.R.OGDEN METHOD

a>b : mesioangular

a=b: vertical

a<b: distoangular

Class I posit ion A Horizontal Class I posit ion B Vert ical

Class I I posit ion A Vert ical Class I I posit ion B Distoangular

A A O M S c l a ss s i f i c a t i o n o f p r o c e du r a l t e r m i no l o g y :

Based on the operation performed to remove an impacted tooth.

It relates directly to abnormal physical findings of other classifications.

A D A c o d e o n p r o c e d u r e s a n d no m e n c la t u r e : The American Dental Association (ADA) Code

describes the amount of soft and hard tissues over the coronal surface of an impacted tooth.

These are described as: soft tissue impactions, partial bony impactions, completely bony impactions, and completely bony impactions with unusual surgical complications.

C omb ined ADA and AA OM S cl as s i fic at i ons :

The AAOMS published the ADA coding with explanations from the AAOMS procedural terminology, in parentheses, as follows:

0 7220 : Removal of impacted tooth – (overlying) soft tissue (Impaction that requires incision of overlying soft tissue and the removal of the tooth).

0 723 0 : Removal of impacted tooth – partially bony impacted (Impaction that requires incision of overlying soft tissue, elevation of a flap, and either removal of bone and tooth or sectioning and removal of tooth.

0 7240 : Removal of impacted tooth – completely bony (Impaction that requires incision of overlying soft tissue, elevation of a flap, removal of bone, and sectioning of tooth for removal).

0 7241 : Removal of impacted tooth – completely bony, with unusual surgical complications (Impaction that requires incision of overlying soft tissue, elevation of a flap, removal of bone, sectioning of the tooth for removal, and/or presents unusual difficulties and circumstances.

P R E - O P A S S E S S M E N T H I S T O R Y chief complaint history of presenting complaint medical history social history E X A M I N A T I O N clinical radiographs

D E C I SI O N diagnosis treatment planning

HISTORYPain and infection associated with partially erupted

teeth.Many impacted or displaced teeth are unerupted and

asymptomatic - incidental finding following radiographic examination.

Occasionally, unerupted wisdom teeth, in the absence of any obvious infection, can give rise to discomfort .

It is important to exclude other possible causes such as TMJ pain and pulpitis / periapical abscess from another tooth

C L I N I C A L E X A M I N A T I O N

Compliant : Pain, exclude other causes such as TMJ disorder, pulpitis/abscess of other teeth.

Previous medical history. Dental history. Extraoral features. Intraoral features.

R A D I O G R A P H I C E V A L U A T I O N

1 . T o st u d y t h e r e l a t i o n w i t h a d j o i n i n g t o o t h.2 . T o st u d y t h e c o n f i g u r a t i o n o f t he r o o t s &

s t a t u s o f t h e c r o w n .3 . T o k n o w t h e b u c c o v e r si o n o r l i n g u o v e r s i o n

o f I mp a c t e d t o o t h .4 . S h a d o w o f t h e e x t e r n a l o b l i q u e r i d g e . I f v e r t i c a l & a n t e r i o r t o t h e I mp a c t e d

t o o t h – P o o r a c c e s s . I f o b l i qu e & p o s t e r i o r t o t h e I m p a c t e d

t o o t h — G o o d a c c e s s .

PERIAPICAL X-RAYS

FRANK’S TUBE SHIFT TECHNIQUE

RELATIONSHIP OF INFERIOR ALVEOLAR NERVE TO THE ROOTS OF THE THIRD MOLAR. (HOWE& POYTON;1960)

Darkening of root Deflection of root Narrowing of root Dark & Bifid apex

Interruption of white Narrowing of canal Diversion of canal l ine of canal

OPG Conventional tomography Facial x-rays lateral oblique views CT Other imaging techniques xeroradiography dentascans intra-oral cameras magnetic resonance imaging

U s e s o f r a d i o g r a p hs :

To determine the type of impaction

Access: the inclination of the external oblique ridge, represented by the radio opaque line.

Existing pathology

Crown of the impacted tooth : large bulbous crown with prominent cusps may present difficulty in smooth delivery.

R o o t s o f t h e i m p a c t e d t o o t h Position and root pattern of the impacted as well as the adjacent

tooth may create difficulty while removing the impacted tooth. These are also the factors which determine the point of application and line of withdrawal.

Radiograph must be carefully examined with reference with the following factors : Fused or separate roots Number of roots Configuration of the roots If curved, is curvature favorable or unfavorable ? Long and slender or short and stout roots. Convergent or divergent

L e ng t h The ideal time to remove the impacted teeth is when the root is

two-thirds formed. I n this stage, the roots will blunt and removal is very easy.

If the tooth is not removed during the formative stage and the entire length of the root develops, the possibility increases for abnormal root morphology and for fracture of the root tips during extraction.

N ot indi cat ed When the root is one-third formed, as the tooth tends roll in its

crypt like ball in a socket, which prevents easy elevation.

The fused, conical roots are easier to remove than widely separated roots.

Severely curved or dilacerated roots are more difficult to remove than straight or slightly curved roots. Convergent roots are comparatively easier to remove than the divergent roots.

The total width of the roots in the mesiodistal direction should be compared with the width of the tooth at the cervical line. If the root width is greater, the extraction will be more difficult.

More bone must be removed or the tooth must be sectioned before extraction.

B o ne t e x t u r e

Bone is cancellous and elastic in the younger age group, while it tends to become dense and sclerosed as the age advances.

The texture of the bone can be gained by noting the size of the cancellous spaces and the density of the bone encircling them in the radiographs. Spaces are large and bone structure fine- elastic bone. Spaces are small and bone shadow dense- sclerotic bone.

In patients of younger age - The bone is less dense, is more likely to be pliable, and expands and bends some what, which allows the socket to be expanded by elevators or by luxation forces applied. The bone is easier to cut with a dental drill and can be removed more rapidly than denser bone.

Patients who are older have denser bone and thus decreased flexibility and ability to expand. So it is not possible to expand the bony socket. It becomes more difficult to remove with a dental drill, and the bone removal process takes longer.

H O W E S T E C H N I Q U E T O P R E V E N T I N F E R I O R A L V E O L A R N E R V E D A M A G E

ARCHER’S MODIFICATION TO PREVENT INFERIOR ALVEOLAR NERVE DAMAGE

Assessment of difficulty for removal of impacted third molar

ASSESSMENT OF POSITION &DEPTH

WHITE LINE It corresponds to the occlusal plane.

It indicates the difference in occlusal level of second & third

molars.

WINTER’S LINES OR WAR LINES

AMBER LINE. Crest of the interdental septum This line denotes the alveolar bone covering

the impacted tooth & the portion of the tooth not covered by the bone.

RED LINE. It indicates the amount of bone that will have

to be removed before elevation i.e. the depth of tooth in bone & the difficulty encountered in removing the tooth.

Length more than 5mm - extraction is difficult.

Every additional millimeter renders the removal of the Impacted tooth 3 times more difficult.

FACTORS RESPONSIBLE FOR INCREASING THE DIFFICULTY SCORE FOR REMOVAL OF IMPACTED 3rd MOLARS

1. Difficult access to the operative field:a. Small orbicularis oris muscle.b. Inability to open mouth wide enough.c. Trismus.d. OSMF.e. Macroglossia.

2. As per the angulation.3. As per the depth.4. As per the space available for the eruption.5. Dilacerated roots.6. Hypercementosis.7. Extremely dense bone.8. Proximity to mandibular canal.9. Ankylosed impacted tooth.10. Large bulbous crown.11. Long slender roots.

D I F F I C U L T Y I N D E X F O R R E M O V A L O F I M P A C T E D L O W E R 3 r d M O L A R SP e d e rs o n ’ s S c a l e R elat io n w i t h r amu s and av ail ab le s p a ce C l a s s I – 1 C l a s s I I – 2 C l a s s I I I - 3

 Po s it io n O f M olar M e s i o a n g u l a r - 1 H o r i z o n t a l – 2 V e r t i c a l - 3 D i s t o a n g u l a r - 4  

R e l a t i v e d e p t h P o s i t i o n A - 1 P o s i t i o n B - 2 P o s i t i o n C - 3

Di f f i c u l t y s c o r e T o t a l R e l a t i v e l y d i f f i c ul t : 3 - 4 M o d e r a t e l y d i f f i c ul t : 5 - 6 V e r y D i f f i c ul t : 7 - 1 0

W H A R F E ’ S A S S E S S M E N T

1 . W inte r 's c l as s if ic at ion Ho riz onta l 2

Dis t oang ul ar 2 Mes i oang ul ar 1

Vert ic al 0 2 . H eig ht of mandib le

1-30 mm 031-3 4mm 135 -3 9 mm 2

3 .A n g u l a t i o n o f 3 r d m o l a r 1 - 5 9° 0

6 0 - 6 9 ° 17 0 - 7 9 ° 2 8 0 - 8 9 ° 3 9 0 ° & a b o v e 4

4 . R o o t s h a p e - R o o t d e v e l o p m en t F a v o ur a b l e c ur v e 1

U n f a v o ur a b l e c u r v e 2 C o m p l ex 3

5.Follicle Normal 0

Possibly enlarged 1 Enlarged 2

6. Path of exitSpace available 0Distal cusp covered 1Mesial cusp covered 2Both covered 3

TOTAL SCORE 33

SURGICAL TECHNIQUE

GENERAL PRINCIPLES FOR SURGICAL TECHNIQUE OF IMPACTION REMOVAL

. Reflect mucoperiosteal flap to obtain good visual

access. Remove labial bone with high speed surgical drill

using round or cross-cut but. Expose crown of impaction upto CEJ and make room

to allow for elevator placement. Attempt to gently evaluate for motility with elevator. Section crown with high-speed surgical handpiece.

Care should be taken to protect the lingual soft tissue and depth of surgical cut should not be too much.

Straight elevator should be used to separate crown from tooth.

Deliver roots with root tip elevators or crane pick. Inspect bony crypt for loose debris and any

bleeding problems and smooth bone margins with bone file.

Carefully remove follicular soft tissue and tease it out from surrounding mucosa.

Copious irrigation of socket and beneath soft tissue

Reapproximate soft tissue flap and close with 3-0 or 4-0 chromic or black silk sutures.

Consider intraoral injection of steroids if extensive bone surgery has been performed. 4mg of dexamethasone can be injected into masseter muscle on each side

Evaluate for post surgical bleeding prior to discharge. flap prior to closure.

BUCCAL VS LINGUAL APPROACH

Criteria Buccal Lingual

Access Relatively easy in the conscious patient Relatively difficult in the conscious patient

Instruments Chisel and mallet or bur Only chisel and mallet

Procedure Tedious Easy

Operating time Time consuming Less time consuming

Technique Easy to perform, hence traditionally popular Technically difficult, hence not popular among all dental surgeons

Bone removal Thick buccal plate Thin lingual plate

Postoperative pain Less More due to the damage of lingual periosteum

Postoperative edema Obviously more Less

Dry socket Incidence is high due to the damage of external oblique ridge

Incidence is negligible since socket is eliminated.

INCISIONS AND FLAP DESIGNS

Parts of incision The incision having three parts:

Limb A: The anterior incision started from a point about 6.4 mm down in the buccal sulcus approximately at the junction of posterior and middle third of the second molar, passes upwards extended upto the distobuccal angel of the second molar at the gingival margin for a distance of 1-2cm.

Limb B: It was carried along the gingival crevice of the third molar extending upto the middle of exposed distal surface of the tooth.

Limb C: Started from a point where intermediate gingival incision ended and was carried laterally towards the cheek at mucosal depth. This arm should be about 25.4 mm long.

In case of unerupted tooth when intermediate gingival incision was not needed. Then limb' A' was extended upto the middle of the distal surface of the second molar.

FLAPS - Principles The base of the flap must be broader than the free margin to preserve an adequate

blood supply. Must be of adequate size - sufficient soft tissue reflection - provide necessary

visualization of the area. The flap should be a full-thickness mucoperiosteal flap. The incisions must be made over intact bone Should be designed to avoid injury to local vital structures in the area of the

surgery. When making incisions in the posterior mandible, especially in the region of the

third molar, incisions should be well away from the lingual aspect of the mandible. In this area the lingual nerve may be closely adherent to the lingual aspect of the mandible, and incisions in this area may result in the severing of that nerve, with consequent prolonged temporary or perma­nent anesthesia of the tongue.

Vertical-releasing incisions should cross the free gingival margin at the line angle of a tooth and should not be directly on the facial aspect of the tooth nor directly in the papilla . Incisions that cross the free margin of the gingiva directly over the facial aspect of the tooth do not heal properly because of tension and result in defect in the attached gingiva.

Flap designs The different types of flaps used are:

L - s h a p e d f l a p : suits only the buccal approach since it is difficult to raise a lingual flap from this approach. The posterior limb of the incision extends from a point just lateral to the ascending ramus of the mandible into the sulcus. It passes disto-lateral periodontium by avoiding or including it -depending upon the proximity of the third molar with the second molar. The junction between the limbs may be curved and incision made in one sweep or it may be angled.

Ba y o ne t fl a p : This incision has three parts: distal or posterior, intermediate or gingival, and an anterior part. The posterior part of the incision goes round the gingival margin of the second and even the first molar, before turning into the sulcus.

Envelop flap: Extends from the mesial papilla of the mandibular first molar and passes around the neck of the teeth to the disto buccal line angle of the second molar. Now the incision line extends posteriorly and laterally upto the anterior border of the mandible. Its anterior extension is directly proportional to the depth at which the impacted tooth is present- deeper the tooth, longer the ant extension

Adv- Easier to close and heal better .

Triangular flap This flap is the result of an L-shaped incision with a

horizontal incision made along the gingival sulcus and a vertical or oblique incision. The vertical incision begins approximately at the vestibular fold and extends to the interdental papilla of the gingiva. The triangular flap is performed labially or buccally on both jaws and is indicated in the surgical removal of root tips, small cysts, and apicoectomies.

A dv a n t a g e s .   Ensures an adequate blood supply, satisfactory visualization, very good stability and reapproximation; it is easily modified with a small releasing incision, or an additional vertical incision, or even lengthening of the horizontal incision.

D i s a d v a nt a g e s .   Limited access to long roots, tension is created when the flap is held with a retractor, and it causes a defect in the attached gingiva.

De s ig n of di s to l i ng u all y b as ed fla p by b uc cal C omma i nci s io n

The incision - a point below the second molar, smoothly curved up to meet the gingival crest at the distobuccal line angle of the second molar. The incision is continued as a crevicular incision around the distal aspect of the second molar.

This comma-shaped incision allows reflection of a distolingually based flap adequately exposing the entire third molar area.

The incision and flap design seems best suited to cases in which the third molar is completely covered with soft tissues. In cases in which part of the impacted tooth is visible in the mouth, a small modification is made.

After the incision , a second incision is made from the distobuccal point on the exposed portion of the third molar to join the first incision approximately midway down . This allows excision of a triangular gingival flap.

Wards incision

Sir TG Ward 1968, made some modification of the incision. The anterior line of the incision runs from the distal aspect of the second molar curving ,downward and forward to the level of the apex of the distal root of the first molar. This second type of incision is used when a linguoverted tooth impaction is present. The posterior part of the incision is the same but the anterior part commences as the junction of the anterior and middle thirds of the second molar and runs down to the apex of the distal root of the first molar.

WARDS INCISION MODIFIED WARDS INCISION

Reflection of flap

Reflection of the flap begins at the papilla. The end of the Woodson elevator or the no. 9 periosteal elevator begins a reflection. The sharp end is slipped underneath the papilla in the area of the incision and turned laterally to pry the papilla away from the underlying bone. This technique is used along the entire extent of the free gingival incision.

Once the flap reflection is started, the broad end of the periosteal elevator is inserted at the middle corner of the flap, and the dissection is carried out with a pushing stroke, posteriorly and apically. This facilitates the rapid and atraumatic reflection the soft tissue flap.

BONE REMOVAL

Aim:1. To expose the crown by removing the bone

overlying it.2. To remove the bone obstructing the pathway for

removal of the impacted tooth.Types:1. By consecutive sweeping action of bur(in

layers). 2. By chisel or osteotomy cut(in sections).How much bone has to be removed? 1. Bone should be removed till we reach below the

height of contour, where we can apply the elevator.2. Extensive bone removal can be minimized by tooth

sectioning.

Sl.No Criteria. Chisel&Mallet Bur

1. Technique Difficult Easy.

2. Controll over bone cutting Uncontrolled Controlled.

3. Patient acceptance. Not tolerated in L.A.

Well tolerated in L.A.

4. Healing of bone. Good Delayed Healing

5. Postoperative edema Less More.

6. Dry socket. Less. More.

7. Postoperative Infection. Less. More.

CHISEL VS BUR

TECHNIQUES FOR REMOVAL OF TECHNIQUES FOR REMOVAL OF DIFFERENT TYPES OF MANDIBULAR DIFFERENT TYPES OF MANDIBULAR 33rdrd MOLAR IMPACTIONS MOLAR IMPACTIONS

Bur technique Most surgeons prefer to use a hand piece with adequate speed and high torque to

remove the overlying bone. The size of the bur used for the removal of the bone removal :

Ideal length – 7mm; diameter – 1.5mm. Large rose head bur (size 12) or fissure bur (no.7) used for gross bone removal. The bur should rotate in correct direction and at maximum speed. Cutting instruments that induce air should not be used. Handpiece should not rest on the tissues of the cheek and lips to avoid burning.

The crown of the impacted tooth should be exposed (CEJ) by removal of surrounding bone: mesially – to create a point of application Buccaly – cutting a trough or gutter around the tooth to the root furcation. Distolingually – lingual plate should not be breached to protect the lingual

nerve.

Copious amount of normal saline is irrigated to avoid thermal necrosis of bone.

To keep the operator field clean an efficient suction should be used.

In the mesial side adequate bone must be removed so that the elevator stands up an angle of 45° to the mandible without any support.

MOORE/GILLBE COLLAR TECHNIQUE

A mucoperiosted flap of standard design is elevated exposing the underlying bone.

A rose-head bur (no.3) is used to create a ‘gutter’ along the buccal side and distal surface of the tooth.

The lingual soft tissue s/b protected with a periosteal elevator during the removal of the distolingual spur of bone

A mesial point of application is created with the bur, and a straight elevator is used to deliver the tooth.

After delivery of the tooth has been effected, the sharp bone edges are smoothed with a vulcanite bur, and the cavity is irrigated.

The wound is closed with sutures or the buccal flap is tucked into the cavity and held against the bone with a pom-pom soaked in Whitehead’s varnish.

C h i e s e l t e c h n i q u e When using chisel - the mandible should be adequately supported. The mallet is used with a loose, free-swinging wrist motion that gives

maximum speed to head of the mallet without introducing the weight of the arm or body into the blow. To plane bone with a chisel, the bevel have to be turned towards the bone. To penetrate the bone, turn the bevel away from the bone.

To restrict the bony cut to the desired extent a vertical limiting cut is made by placing a 3 mm or 5 mm chisel vertically at the distal aspect of the II molar with the bevel facing posteriorly.

Its approximate height is 5-6 mm. Then the chisel is placed at an angle of 45° at the lower edge of the limiting cut in an oblique direction.

This will result in the removal of a triangular piece of buccal plate distal to the II molar.If necessary, bony cut can be enlarged to uncover the impacted tooth to the desired level.

Finally.distal bone must be removed so that when the tooth is elevated, there is no obstruction at the distobuccal aspect.

I r r i g a t i o n The surgeons should apply a handpiece load of approximately 300g and an

irrigation rate of 15 mL/min (for intermittent drip) to 24 mL/min (for continuous flow).

The various solutions which can be used as irrigants are: Saline Sterile water Ringer’s lactate. 1% povidone iodine

The irrigation cools the bur and prevents bone-damaging heat buildup. The irrigation also increases the efficiency of the bur by washing away bone chips from the flutes of the bur and by providing a certain amount of lubrication.

A large plastic syringe with a blunt I8-gauge needle is used for irrigation purposes. The needle should be blunt and smooth so that it does not damage soft tissue, and it should be angled for more efficient direction of the irrigating stream

Bone belongs to the patient and the tooth belongs to the surgeon.

This implies the tooth division technique. Pell and Gregory stated the following advantages

of splitting technique: Amount of bone to be removed is reduced. The time of

operation is reduced. The field of operation is small and therefore damage to

adjacent teeth and bone is reduced. Risk of jaw fracture is reduced. Risk of damage to the inferior alveolar nerve is reduced

S e c t i o n i ng o f t h e t o o t hS e c t i o n i ng o f t h e t o o t h

Sectioning of the tooth

Sectioning of a tooth can be carried out with a bur or with an osteotome Sectioning of teeth with a bur is safe and technically easy, whereas the osteotome

technique is quicker but more hazardous. If bur is used it should be the fissure type, and about size No.8, but a surgical pattern

with a longer cutting surface. A tapered fissure bur is less likely to jam or break than the standard crosscut bur during the process of cutting either bone or tooth substance.

If an osteotome is used for tooth division it should be about 6.4 mm (1/4 in) in width and have a handle of about 17.5cm (7 in) in length.

When splitting a tooth longitudinally through the root bifurcation the osteotome blade should be placed in the buccal anatomical groove between the mesial and distal coronal cusps at an angle of 450 to the vertical axis of the tooth.

Mesioangular impaction

Horizontal impaction

Vertical impaction

Distoangular impaction

Li ng u al s pl i t b one t ec hniq u e(Kelsey Fry , T. Ward) Useful- removal of deeply positioned

horizontal distoangular impactions (Rud, 1970).

First, a vertical stop cut about 5 mm in height is made with a 3 mm width chisel in the buccal cortex immediately distal to the second molar.

A second vertical stop cut will be made about 4 mm disto-buccal to the third molar crown.

The two cuts will then be joined, and the

buccal plate covering the crown will be removed

The distolingual bone is now fractured inward by placing the chisel at an angle of 45° to the bone surface and pointing in the direction of second premolar on the contralateral side.

The cutting edge of the chisel is kept parallel to the external oblique ridge and a few light taps are given with the mallet which separates the lingual plate from the alveolar bone.

The "peninsula" of bone which then remains distal to the tooth and between the buccal and lingual cuts js excised.

care must be taken that the cutting edge of the chisel is not held parallel to the internal oblique ridge as this may lead to the extension of the lingual split to the coronoid process.

A sharp, pointed, fine-bladed straight elevator is then applied to displace the tooth upward and backward out of its socket.

As the tooth moves,backward, the fractured lingual plate is displaced from its path of withdrawal, thus facilitating delivery of the tooth.

The fractured lingual plate is then

lifted from the wound, thus completing the saucerization of the bony cavity..

A DVA N T AGES

Faster tooth removal. Less risk of inferior alveolar nerve damage.Reduces the size of residual blood clot by means of saucerization of the socket .Decreased risk of damage to the periodontium of the second molar. Decreased risk of socket healing problems.

DRAWBACKS Risk of damage to the lingual nerve. The incidence of lingual nerve and inferior alveolar nerve damage has been reported as 1- 6.6% .Increased risk of postoperative infectionPatient discomfort due to the use of a chisel and mallet for lingual bone removal or fracturing.Only suitable for young patients with elastic bone

DRAWBACKS OF THIS TECHNIQUE ARE:

Risk of damage to the lingual nerve.

Increased risk of postoperative infection and greater danger of spread. Patient discomfort due to the use of a chisel and mallet for lingual bone removal or fracturing. Only suitable for young patients with elastic bone in which grain is prominent

Modified distolingual bone splitting technique Davis's technique mentions not to separate the mucoperiosteum

from lingual area of bone. The bone was released in segments to allow tactile control of osteotome to prevent penetration of the osteotome into soft tissue.

Lewis technique: Lewis (1980) modified the lingual split-bone technique by minimizing periosteal reflection and buccal bone removal and by preserving the fractured lingual plate. He claims that these modifications reduce the possibility of lingual nerve damage, minimize periodontal pocket formation, and improve the chances for primary wound healings.

Lateral trephenation technique This procedure was first described

by Bowdler-Henry to remove any partially formed and unerupted third molar in the age group of 9-16 years.

Modified S-shaped incision is made from retromolar fossa across the external oblique ridge. It then curves down to the I molar anteriorly in the vestibule.

The mucoperiosteal flap is elevated and buccal cortical plate is trephined over the III molar crypt. bur is used to make vertical cuts anteriorly and posteriorly.

A chisel or an osteotome is applied in the vertical direction over the bur holes. Then the buccal plate is fractured out, exposing the third molar crypt completely.

Elevator is applied to deliver the tooth out of the crypt. Any follicular remnant present in the crypt is carefully scooped out, avoiding injury to the inferior alveolar (dental) canal at the lower part of the crypt.

Advantages: Partially formed unerupted 3rd molar can be removed. Can be preformed under general or regional anesthesia with

sedation. Post-op pain is minimal. Bone healing is excellent and there is no loss of alveolar

bone around the 2nd molar.

Disadvantages : Virtually every patient has some post operative buccal swelling

for 2-3 days after surgery

Wound toilet It is important to irrigate the surgical site,

with particular attention paid to the space directly underneath the buccal flap where loose debris may accumulate and cause a buccal space infection.

Adequate haemostasis is also important prior to wound closure to minimize the risk of persistent postoperative oozing and haematoma formation.

Closure The most important suture is the one

placed immediately behind the second molar, ensuring there is accurate apposition of wound edges .

It is also useful to place a suture across the distal incision where the soft tissue thickness and potential bleeding source is greatest.

Many clinicians often do not place sutures across the buccal relieving incision, which permits a dependent area of drainage.

Watertight closure is unnecessary and may in some cases increase postoperative pain and swelling.

Primary closure of the wound should not be attempted unless – atleast 5mm of a band of buccal attached mucoperiosteum is present.

Tube drain when using primary wound

closure, a small surgical tube drain or gauze strip may be inserted in buccal incision before suturing to facilitate drainage. It should be removed after 24-72 hours. With this technique, the postoperative problems of the Patient are expected to be less severe.

SURGICAL CLOSURE

1) Wedge removal 2) Debridement 3) Intra-alveolar

dressings 4)Closure of soft

tissue flap5) Intraoral

dressings

SURGICAL SIDE-EFFECTS AND COMPLICATIONS

Intra operative complications:

1. During incision a.Injury to facial artery.b.Injury to lingual nerve.

2. During bone removal

a. Damage to second molar.b. Slipping of bur into soft tissue & causing

injury.c. Fracture of the mandible when using chisel &

mallet.

a. Luxation of neighbouring tooth.b. Soft tissue injury due to Slipping of elevator.c. Injury to inferior alveolar neurovascular bundle.d. Fracture of mandible.e. Forcing tooth root into submandibular space or inferior alveolar canal.f. Breakage of instruments.g. TMJ Dislocation.

3.DURING ELEVATION OR TOOTH REMOVAL

POST OPERATIVE COMPLICATIONS:

a. Dry socket. Incidence-3%(Heasman,1987) Predisposing factors-smoking,pre-

existing infection,birth control medication,extensive bone removal.

b. Pain.

c. Trismus.

d. Infection

e. Swelling.

f. Paresthesia of Lingual or Inferior alveolar nerve.

-Over 96% of pts with IAN injury & 87% of those with lingual n. injuries recover spontaneously (Alling)

-Spontaneous recovery-9months(Mozsary,1987)

REFERENCES

Impacted teeth – Charles C. Alling Textbook of oral and maxillofacial surgery, vol.

2, Laskin. Oral and maxillofacial surgery-Archer The impacted wisdom tooth – Killey & Kay Textbook of oral & maxillofacial surgery – SM Atlas Oral Maxillofacial Surg Clin N Am 20 (2012)

197–223