TMJ (Temporo Mandibular Joint)“Joint Of The Law”

CONTENTS Introduction Joint and Types of joints Peculiarity of TMJ Development of TMJ Components of TMJ Blood and Nerve supply to TMJ Biomechanics/Movements of TMJ Age changes in TMJ Clinical examination of TMJ Clinical anatomy and TMJ disorders Christensen’s TMJ implant Conclusion

INTRODUCTION Why it is called temporomandibular

joint????

What are the other names???

Craniomandibular joint

Most complex joint in the body.

Compound joint.

Ginglymoarthroidal joint.

Modified ball and socket joint.

Most important functions of TMJ are….???? Unique in that it constitutes of two separate joints anatomically a

Ref: WILLIAMS PL:GRAY’S ANATOMY IN SKELETALSYSTEM;38TH ed;pg:578

JOINT AND TYPES OF JOINTS

Classification of joints FIBROUS JOINTS (SYNARTHROSES)

1.SUTURES

2.SYNDESMOSES

3.GOMPHOSES CARTILAGINOUS JOINTS (AMPHIARTHROSES)

1. SYNCHONDROSES (Hyaline cartilage)

2.SYMPHYSES (Fibrocartilage) SYNOVIAL JOINTS (DIARTHROSES)

1.UNIAXIAL

(A)GINGLYMUS (Hinge)

(B)TROCHOID (Pivot)

2.BIAXIAL

(A)CONDYLOID (B)SADDLE

3.TRIAXIAL

(A)BALL AND SOCKET (B)PLANAR

Unique in that it constitutes of two separate joints anatomically and they function together as a single unit

PECULIARITY OF TMJ

Bilateral diarthrosis

Articular surface covered by white fibrous cartilage instead of hyaline cartilage.

Only joint in human body that have a rigid end point ,due to closure of teeth making occlusal contact

In contrast to other diarthroidal joints,TMJ is last to devolop( i.e., in about 7th week of uterine life)

TMJ devolops from distinct blastema.

DEVELOPMENT OF TMJ

Early TMJ develops from the first branchial arch mesenchyme and is therefore innervated by fifth cranial nerve. This is the early embryonic joint.

This early embryonic joint is the joint between malleus and incus which develops from first branchial arch.

This joint serves as the primary TMJ joint up to 16 weeks of prenatal life. This joint is an uniaxial hinge joint capable of no lateral motion.

Development…..

By the end of 7-11 weeks of gestation,the secondary TMJ begins to devolop .

i.e., At about 9th week – a condensation of mesenchyme appears surrounding the upper posterior surface of rudimentary ramus( joint capsule devolops from the condensed mesenchyme)

At about 12 th week of IUL,2 clefts appear in that mesenchyme - producing the upper and lower joint cavities.

Development…..

The remaining intervening mesenchyme – becomes the intra articular disc.( which will be well defined by 16th week of IUL)

At birth – mandibular fossa( in temporal bone) is flat, with out any articular eminence, this becomes prominent only after the eruption of deciduous dentition.

RELATIONS OF TMJ

Laterally –

skin,fascia , parotid gland , Temporal branches of 7th cranial nerve

Medially – Tympanic plate seperates TMJ from internal carotid artery,spine of sphenoid with upper end of sphenomandibular ligament,Auriculotemporal and chorda tympani nerve,Middle meningeal artery

RELATIONS……

Anteriorly – Lateral pterygoid muscle,Masseteric nerves and vessels.

Posteriorly – Parotid gland seperates it from external acoustic meatus.

Superiorly – Middle cranial fossa

Inferiorly – Maxillary artery and vein,Middle meningeal vessels

COMPONENTS OF TMJ

TMJ is complex both morphologically and functionally.

An articular disc composed of dense fibrous tissue is interposed between temporal bone and mandible dividing the articular space in to upper and lower compartments.

Gliding movements occurs in upper compartment and hinge movements occurs in lower compartment.

The articulating surface of TMJ are lined by dense ,avascular fibrous connective tissue.

COMPONENTS ….

Articular surfaces of Temporal bone

Mandibular condyle

Articular disc

Ligaments

Muscular components

Articular surfaces

Upper articular surfaces:

I)Articular tubercle

II) Anterior part of the mandibular fossa

III) Posterior non-articular part formed by tympanic plate

Articular surfaces

Lower articular surfaces:

I) Head of the mandible

Ligaments

They are

I) Fibrous capsule

II) Lateral temporo-mandibular ligament

III) Spheno-mandibular ligament

IV) Stylo-mandibular ligament

Fibrous capsule

Attachment:

Above: (From ant to post)

I) Articular tubercle

II) Mandibular fossa

III) Squamo tympanic fissure

Below:

Neck of the mandible

Temporomandibular ligament

It is attached above to the articular tubercle

Below: posterolateral aspect of neck of mandible

It primarily reinforces and strengthens the capsular ligament

Spheno-mandibular ligament

An accessory ligament

of TMJ

Above: spine of

sphenoid

Below: Lingula of

mandibular foramen

It is the remnant of

Meckel’s cartilage

Stylo-mandibular ligament

An another accessory ligament of TMJ

Attachment:

Above: Styloid process

Below: Posterior border of

ramus of mandible

It represents the thickened

part of deep fascia that

divides parotid and

submandibular regions.

Articular disc It is an oval plate of fibro-cartilage

which caps the head of mandible. It divides the joint into two compartments

I) Menisco-temporal

II) Menisco-mandibular

Morphologically it represents the

primitive insertion of lateral

pterygoid.

Attachment:

Ant: Blends with fibrous capsule

Post: It splits into two lamellae

I) Upper lamella: It is attached to the squamo-tympanic fissure

II) Lower lamella: It is attached to posterior surface of neck of mandible.

Functions of articular disc

The upper surface is concavo-convex which provides a friction-free gliding surface for the condyle of mandible.

Presence of articular disc may also reduce wear because the friction is nearly halved.

Alternate theory:

The articular disc forms slippery surface with no friction force dislocation

The position is largely controlled by neuromuscular forces

Blood supply & Innervation- TMJ

Blood supply:

Superficial temporal and maxillary arteries

The Blood supply to TMJ is majorly Superficial, i.e there is no blood supply inside the capsule

TMJ takes its nourishment from Synovial fluid

Nerve supply:

Masseteric and auriculotemporal nerves

Hilton’s Law:The principle that the nerve supplying a

joint also supplies both the muscles that move the joint and the skin covering the articular insertion of those muscles

Auriculotemporal nerve

maxillary artery

Masseteric nerve

Superficial temporal

artery

Movements of TMJ

Rotational movement occurs in first 20-25mm of mouth opening

Translational movement after that when the mouth is excessively opened

Movements…..1. Depression Of Mandible

Lateral pterygoid Digrastric Geniohyoid

2. Elevation of Mandible Temporalis Masseter Medial Pterygoids

3. Protrusion of Mandible Lateral Pterygoids Medial Pterygoids

4. Retraction of Mandible Posterior fibres of

Temporalis

Age changes of the TMJ:

Condyle: Becomes more flattened Fibrous capsule becomes thicker. Osteoporosis of underlying bone. Thinning or absence of cartilaginous zone.

Disk: Becomes thinner. Shows hyalinization and chondroid changes.

Synovial fold: Become fibrotic with thick basement membrane.

Blood vessels and nerves: Walls of blood vessels thickened. Nerves decrease in number

These age changes lead to:

Decrease in the synovial fluid formation

Impairment of motion due to decrease in the disc and capsule extensibility

Decrease the resilience during mastication due to chondroid changes into collagenous elements

Dysfunction in older people

CLINICAL EXAMINATION OF TMJ

1. History taking

2. Measuring maximum interincisal opening

3. Palpation of pretragus area ; the lateral aspect of TMJ

4. Intra – auricular palpation ; the posterior aspect of TMJ

5. palpation of masseter muscle

6. Palpation of lateral pterygoid muscle

7. Palpation of medial pterygoid

8. Palpation of temporalis

9. Palpation of sternocliedomastoid

10. Palpation of digastric

SCREENING HISTORY AND EXAMINATION

Because the prevlance of TMD is very high , every patient who comes to dental office should be screened for these problems

The purpose of screening history is to identify patients with subclinical signs and symptoms that the patients may not relate but are commonly associated with functional disturbances of masticatory system (headache , ear symptoms)

The screening history consists of several questions that will help orient the clinician to any TMD.

QUESTIONS TO BE ASKED:

:

Do you have pain in the face,front of ear and the temple area? Do you get headaches , earaches , neckache , or cheek pain? When is the pain at its worst ? Do you experience pain when using the jaw? Do you experience pain in the teeth? Do you experience joint noises when moving your jaw or chewing? Does your jaw ever lock or get stuck? Does your jaw motion feel restricted? Have you had any jaw injury? Have you had treatment for jaw symptoms? if so ,what was the

effect? Do you have any other muscle , bone , or joint problem such as

arthritis?

TMJ DISORDERS

Temporomandibular joint disorders, or TMJ disorders, are a group of medical problems related to the jaw joint.

TMJ disorders can cause headaches, ear pain, bite problems, clicking sounds, locked jaws, and other symptoms that can affect quality of life for the patient.

Classification of TMJ Disorders:

1. Developmental Disorders of TMJ

2. Degenerative Joint Disease

3. Inflammatory Disorders

of the Joint

4. Traumatic Disorders of TMJ

5. Metabolic Disorders

6. Neoplastic Disorders

7. TMJ Disorders Syndrome or Myofacial Pain Dysfunction Syndrome

Temporomandibular joint dysfunction

syndrome Temporomandibular joint dysfunction (sometimes abbreviated to TMD or TMJD and also termed temporomandibular joint dysfunction syndrome, temporomandibular disorder or many other names), is an umbrella term covering pain and dysfunction of the muscles of mastication (the muscles that move the jaw) and the temporomandibular joints (the joints which connect the About 20% to 30% of the adult population are affected to some degree.

Pain is constant, dull in nature, in contrast to the sudden sharp, shooting, intermittent pain of neuralgias.

The cause of MPD is controversial although it is generally considered to be multifactorial

Usually people affected by TMD are between 20 and 40 years of age, and it is more common in females than males.

TMD is the second most frequent cause of orofacial pain after dental pain (i.e. toothache).

TMJD’S……

Cardinal symptoms of MPDS :-

1. Pain or discomfort anywhere about the head or neck.

2. Limitation of motion of the jaw.

3. Joint noises– grating,clicking,snapping.

4. Tenderness to palpation of the muscles of mastication.

TMJD’S…….

Even though there are many treatments available, there is a general lack of evidence for any treatment in TMD, and no widely accepted treatment protocol exists.

Common treatments that are used include provision of occlusal splints, psychosocial interventions like cognitive behavioural therapy, and medications like analgesics (pain killers) or others

TMJ DISLOCATION

The mandible can dislocate in the anterior, posterior, lateral, or superior position. Description of the dislocation is based on the location of the condyle in comparison to the temporal articular groove.

Anterior dislocations are the most common and result in displacement of the condyle anterior to the articular eminence of the temporal bone. These dislocations are classified as acute, chronic recurrent, or chronic

TMJ dislocation may occur with trauma, but most often follows extreme opening of the mouth during yawning, laughing, singing, vomiting, or dental treatment .

Dislocation also can result from dystonic reactions to drugs .

Symmetric mandibular dislocation is most common, but unilateral dislocation with the jaw deviating to the opposite side also can occur.

TMJ dislocation is painful and frightening for the patient.

TMJ DISLOCATION….

TMJ ANKYLOSIS

Ankylosis of the TMJ most often results from trauma or infection.

True bilateral congenital ankylosis of the TMJ leads to micrognathia or “bird face”.

If ankylosis affects only one side, it produces a lateral deviation of the jaw to the non-affected side, due to the fact that this side continues its growth normally.

TMJ Radiographic views The various TMJ views are:

Transcranial view……. helps in the visualization of the superior surface of the condyle and the articular eminence.

Transorbital view………Zimmer projection or transmaxillary projection. This view demonstrates the entire lateromedial articulating surfaces of both the condyle and the articular eminence and the condylar neck.

Transpharyngeal view…………also called as infracranial view, Parma projection, or McQueen projection. This projection demonstrates the condylar process from the midmandibular ramus to the condyle. This technique helps in the diagnosis of fractures of the condyle and the condylar neck and in detecting alterations in the condylar morphology.

TMJ tomography…………….. Tomography is a technique used to demonstrate structures located within a particular plane while blurring out structures outside this plane, Tomography helps in the visualization of the condyle, the articular eminence, and the glenoid fossa. It can also be used to determine the joint space.

LAB INVESTIGATIONS

No tests may be needed in straightforward cases.

Possible investigations are:

1.Blood tests: ESR, CRP for inflammation.

2.Plain radiographs - show gross bony pathology such as degeneration or trauma.

3.CT or MRI scan of the joint. MRI scan shows the soft tissues and intra-articular disc well.

4.Ultrasound - this is a useful alternative imaging technique for monitoring TMJ disorders.

5.Diagnostic nerve block.

6.Arthroscopy.

TMJ SURGERIES

Surgery may be indicated for some patients, mainly when conservative treatments are not successful.

It is usually supported by non-invasive treatment before and afterwards.

Surgical options include:

1. Arthrocentesis

2. Therapeutic arthroscopy.

3.Removal of loose bone fragments.

4.Reshaping the condyle.

5.More complex procedures, including joint replacement,depending on the pathology involved.

Temporomandibular joint surgery: what does it mean to the dental

practitioner

In March 2011, G Dimitroulis in vincents hospital melbourne assesed why dental practioners should be aware of benefits and risks of TMJ surgeries.

They concluded that all dental practitioners should be aware of the benefits of TMJ surgery so that patients do not suffer unnecessarily from ongoing non-surgical treatments that ultimately prove to be ineffective in the management of their condition.

Temporomandibular joint problems and periodontal condition in rheumatoid

arthritis patients

In December 2011, Garib BT1 and Qaradaxi SS in College of Dentistry, University of Sulaimani, Kurdistan assesed Temporomandibular joint problems and periodontal condition in rheumatoid arthritis patients in relation to their rheumatologic status.

They took plaque index, bleeding index, clinical attachment loss, radiographic bone loss, tooth loss, and TMJ problems were assessed in the 2 groups.

They concluded that Patients with advanced RA are more likely to develop more significant periodontal and TMJ problems compared with patients with PD and without RA. There is a great need to instruct patients with RA to consult a dentist to at least decrease PD severity.

Periodontal Related TMJ

Disorders(journals)……. There are several areas where TMJ disorders may

impact which are , namely ……..dental caries, periodontal disease, saliva abnormalities, oral health and the effect of facial growth.

The relationship of bruxism with TMD is debated. Many suggest that sleep bruxism can be a causative or contributory factor to pain symptoms in TMD.

Indeed, the symptoms of TMD overlap with those of bruxism. Others suggest that there is no strong association between TMD and bruxism.

Christensen’s TMJ prosthesis(Implant)

REF: Christensen TMJ Fossa-Eminence Prosthesis System: a retrospective clinical study.Britton C1, Christensen RW, Curry

JT.

A partial TMJ prosthesis consists of a meniscectomy and placement of a metallic glenoid fossa metal prosthesis (Christensen fossa prosthesis) in place of the meniscus, such that a natural condyle articulates with a metal fossa prosthesis. There is inadequate evidence of the safety and effectiveness of partial joint prostheses in the treatment of TMD.

CONCLUSION

It is impossible to comprehend the fine points of occlusion without an in depth awareness of anatomy ,physiology ,and biomechanics of the TMJ.

The first requirement for successful occlusal treatment is stable, comfortable TMJ.

The jaw joints must be able to accept maximum loading by the elevator muscles with no signs of discomfort.

It is only through an understanding of how the normal, healthy TMJ functions that we can make sense out of what is wrong when it isn't functioning comfortably.

This understanding of TMJ is foundational to diagnosis and treatment.

References

1. Gray’s Anatomy

2. Fundamentals of occlusion and TMJ disorders

-- Okeson

3.B.D.Chaurasia

4. Grant’s Atlas of Human Anatomy

5. Occlusion – Ash RamfJord

6. Orthodontics Principles and Practice

-- T.M.Graber

7. Joseph H. Kronman et al (ajodo 1994;105:257-64.)

8. Stavros Kiliaridis et al ,European Journal of

Orthodontics 25 (2003) 259–263

9.Wikipedia

Guided by

Dr.Narendra dev sir,

Dr.vajra madhuri mam,

Dr.Lahari mam.

THANK YOU……..One and All.

Kindly Let Me KnowIf you have any

doubts…..