TMJ ANATOMY AND ASSOCIATED NEUROMUSCULAR DISORDERS

DR. AJAY SRINIVASDEPT OF ORTHODONTICS

PG STUDENT

CONTENTS

• INTRODUCTION• CLASSIFICATION OF JOINTS• TMJ ANATOMY• MUSCLES OF MASTICATION• TMJ IMAGING• TMJ DISORDERS• USE OF ORTHODONTICS IN TMD TREATMENT• REFERENCES

INTRODUCTIONTMJ IS A: COMPOUND BICONDYLAR GINGLIMO-ARTHROID ELIPSOIDAL SYNOVIAL JOINT.

The TMJ influences the function, esthetics, & structural harmony of the teeth, dentition, face and thus a person in total.Therefore an understanding of the anatomy , physiology, biomechanics of the masticatory system is very much necessary.

Classification of Joints3 TYPES:

1. FIBROUS: IMMOVABLE JOINT

2. CARTILAGENOUS JOINT : LIMITED MOVEMENT

• PRIMARY• SECONDARY

• 3. SYNOVIAL JOINT: permits free movement between two bones; surrounded by capsule enclosing joint cavity filled with synovial fluid. Eg: TMJ

TMJ ANATOMY

BONY COMPONENTS SOFT-TISSUE COMPONENTS 1. Glenoid fossa 1. Articular disk 2. Condylar head 2. Joint capsule 3. Articular eminence 3. Ligament

BONY COMPONENTS

GLENOID FOSSA

The glenoid fossa is the depression in the temporal bone that articulates with the mandible. In the temporal bone, it is bounded, in front, by the articular tubercle; behind, by the tympanic part of the temporal bone, which separates it from the external acoustic meatus; it is divided into two parts by a narrow slit, the petrotympanic fissure (Glaserian fissure). It is also referred to as the mandibular fossa.

CONDYLAR HEAD• Oval – mediolaterally • 15-20 mm long (M-L); 8-10 mm wide (A-P); 8-12 mm thick• Medial pole is more prominent than lateral pole.• Articulating surface is convex anteroposteriorly & slightly convex

mediolaterally.

Anterior viewPosterior view

Medial pole more prominent than lateral pole

Articular surface of Posterior aspect > anterior aspect

• A line drawn through the centers of the poles of the condyles, usually extends medially & posteriorly towards the anterior border of the foramen magnum.

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ARTICULAR EMINENCE

Its Sigmoid in shape and has Anterior & posterior slopes Saddle – shaped in coronal section – concave mediolaterally Along with articular disc, it guides mandibular movement during jaw opening

SOFT-TISSUE COMPONENTS

• Articular disc Seperating the 2 bones from direct

articulation is the Articular disc. It serves as a non ossified bone that permits complex movements of the joint.

- The disc is composed of dense fibrous connective tissue

AB- anterior border PB- posterior border IZ- intermediate zone

Anterior view –

the disc is slightly thicker medially than laterally.

LP- lateral poleMP- medial pole

• The articular disc is attached to the capsular ligament ,not only anteriorly & posteriorly, but also medially & laterally; this attachment divides the joint into :

a) the upper cavity [superior cavity] b) the lower cavity [inferior cavity]

• Specialized endothelial cells forms a synovial lining surrounding the internal surface of the cavities.

• This lining along with a specialized synovial fringe located at the anterior border of the retrodiscal tissues, produce synovial fluid.

Synovial Fluid – i) It provides metabolic requirements to the non-vascular

articular surfaces of the joint. ii) provides lubrication during function,thus reducing

friction.

• Lubrication – 2 typesi) Boundary lubricationii) Weeping lubrication

• Boundary lubrication – -when the joint moves, the synovial fluid is forced from

one area of the cavity to another. -prevents friction & is the primary mechanism of joint

lubrication• Weeping lubrication – -due to the ability of the articular surfaces to absorb a

small amount of fluid. -forces during function drive a small amount of fluid in &

out of the articular tissues,this helps in metabolic exchange.

LIGAMENTS• They are Non-elastic collagenous structures which restrict and

limit the movements of a joint .• They restrict the distance by which articulating bones can be

separated from each other without causing tissue damage• According to definition– joint capsule is also a ligament• True ligaments:

1. COLLATERAL / DISCAL LIGAMENTS

2. CAPSULAR LIGAMENT

3. TEMPOROMANDIBULAR / LATERAL LIGAMENT• Accessory ligaments:

1. SPHENOMANDIBULAR LIGAMENT

2. STYLOMANDIBULAR LIGAMENT

• Collateral (discal ligaments) :

- Attaches the medial & lateral borders of the articular disc to the

poles of the condyles.

- Divides the joint mediolaterally into the superior & inferior cavities.

- True ligaments , do not stretch & restricts movement of the disc away from condyle.

- They are Responsible for hinging movement of the TMJ.

- They Have both vascular supply as well as neural innervation , providing movement information regarding joint position .

- Strain on these ligaments produces pain.

Capsular ligament-

- surrounds & encompasses the entire TMJ. - attached superiorly to the temporal bone along the borders

of the articular surfaces of the mandibular fossa & articular eminence.

- attached inferiorly – to the neck of the condyle - resist any medial, lateral / inferior forces that tend to

separate or dislocate the articular surfaces. - helps to retain synovial fluid & provides proprioceptive

feedback.

Temporomandibular (Lateral) ligament 2 parts- • IHP- Inner horizontal portion • OOP- Outer oblique portion

Oblique portion – resists excessive dropping of the condyle - aids in normal opening of the mouth. - in wider mouth opening- the condyle moves downwards

& forward across the articular eminence.

• Accessory ligaments ; i) the sphenomandibular ligament ii) the stylomandibular ligament

• Innervation of TMJ –

- The trigeminal nerve , provides both motor & sensory innervation to the muscles that control it.

- Afferent innervation – by branches of the mandibular nerve. - Also by auriculo-temporal nerve as it leaves the mandibular

nerve behind the joint & ascends laterally & superiorly to wrap around the posterior region of the joint.

- Additional nerves – are deep temporal & masseteric nerve.

• In addition to the above mentioned nerves the tmj capsule also contains three types of mechanoreceptors.

Mechanoreceptor Nature of the receptor

Ruffini proprioception

Golgi tendon Static mechanoreceptor

Pacinian receptor Dynamic mechanoreceptor

• Vascularization – i) posteriorly- superficial temporal artery ii) anteriorly- middle meningeal artery iii) inferiorly- internal maxillary artery iv) other arteries are - the deep auricular - anterior tympanic - ascending pharyngeal arteries - condyle, receives supply through its marrow spaces by

“feeder vessels” from inferior alveolar artery.

Lymphatic drainage

AREA OF TMJ DRAINING LYMPH NODE

Anterior surface parotid lymph nodes

Posterior surface submandibular nodes

Lateral surface preauricular lymph node

Medial surface submandibular nodes

MUSCLES OF MASTICATION

- MASSETER

- TEMPORALIS

- LATERAL PTERYGOID

-MEDIAL PTERYGOID

MASSETER

• Has 3 layers: superficial, middle & deep.• Has Multipinnate arrangement of fibers • It’s a Quadrilateral muscle that covers lateral surface

of the mandible.

TEMPORALIS

Fills the Temporal Fossa. FAN shaped muscle.

MUSCLE ORIGIN FIBERS INSERTION

TEMPORALIS TEMPORAL BONE AND FASCIA

CONVERGE & PASSES THROUGH GAP DEEP TO ZYGOMATIC ARCH

- MARGIN & DEEP SURFACE OF CORONOID- ANT. BORDERS OF RAMUS OF MAND.

LATERAL PTERYGOID

ORIGIN FIBERS INSERTION

UPPER (SMALL) FROM INFRATEMPORAL SURFACE & CREST OF G.WING OF SPHENOID

RUN BACKWARDS & LATERALLY.CONVERGE FOR INSERTION

PTERYGOID FOVEA (CONDYLAR NECK)

LOWER(LARGER)

LATERAL SURFACE OF LATERAL PTERYGOID PLATE

ANT. MARGIN OF ARTICULAR DISC & CAPSULE OF TMJ.

MEDIAL PTERYGOID

ORIGIN FIBERS INSERTION

SUPERFICIAL(SMALL)

TUBEROSITY OF MAXILLA & ADJOINING BONE

DOWNWARDS, BACKWARDS & LATERALLY

MEDIAL SURFACE OF ANGLE & RAMUS OF MANDIBLE

DEEP(LARGE)

MEDIAL SURFACE OF LATERAL PTERYGOID PLATE & ADJOINING PROCESS OF PALATINE BONE

BELOW & BEHIND MANDIBULAR FORAMEN & MYLOHYOID GROOVE

• The relationship between the disk & the lateral pterygoid muscle---

The foot of the anterior part of disc blends with the capsule and provides a mechanism by which the foot is attached to the roof of the superior head of the lateral pterygoid muscle..

Examination of TMJ FOLLOWING ARE NOTED- Palpation – in closed position, at rest & various open

positions Deviation should be noted Crepitus / abnormal sound Palpation of the neck & sub mandibular area Speech evaluation Facial asymmetry Pain in head & neck region Opening movement Examination of soft tissues Examination of occlusion

Path of openingAlterations

1. Deviation

2. Deflection

DEVIATION is any shift of the midline during opening that disappears with continued opening (i.e. returns to midline)

DEFLECTION is shift of midline to one side that becomes greater with opening and is maintained in that position at maximum opening (i.e. does not return to midline)

Lateral movements

Less than 8mm is recorded as restricted movement

MAXIMUM JAW OPENING

• The distance between the incisal edges of the upper and lower central incisors is measured with a Boley gauge.

• The normal range of mouth opening is between 38-45mm.

• In overbite cases this amount is added to the obtained value whereas in open bite it is subtracted.

-Patient is asked to open slowly until pain is first felt….This is the MAXIMUM COMFORTABLE OPENING.

-The patient is then asked to open the mouth maximally…..This is recorded as the MAXIMUM OPENING.

-If the mouth opening is restricted it is helpful to test the END FEEL.END FEEL- DESCRIBES CHARACTERISTICS OF RESTRICTION. IT CAN BE EVALUATED BY PLACING FINGERS BETWEEN PATIENTS UPPER AND LOWER TEETH & APPLYING STEADY FORCE TO PASSIVELY INCREASE INTERINCISSAL DISTANCE.-A SOFT END FEEL suggests MUSCLE INDUCED RESTRICTION.

-HARD END FEELS are more likely to be associated with intracapsular sources(Eg. DISC DISLOCATION)

Palpation of T.M.J.

• Pain or tenderness of TMJ is determined by digital palpation when the mandible is in both stationary and dynamic movements.

• The examiners finger tips are placed over the lateral aspect of joint areas simultaneously on both sides.

• 4 point scale is used-• 0=pressure only,no pain 2=chronic pain• 1=pain on pressure only 3=patient grabs the dentist hand because of pain.

Lateral palpation• The finger tips should feel the

lateral poles of condyles passing down towards articular eminence.

• Once position is verified, the medial force is applied to the joint area to check for any pain

Posterior palpation:

• Position the little finger in the external auditory meatus and palpate the posterior surface of condyle during opening and closing of the mandible.

• Palpation is done in such a way that the condyle displaces the little finger when in full occlusion.

AUSCULATION OF THE T.M.J.

• Sounds made by the TMJ can be examined with a stethoscope. Also the timing of clicking during opening and closure can be noted .

Clicking

• It occurs due to the uncoordinated movement of condylar head and T.M.J disc.

• Joint clicking is differentiated as:Initial IntermediateTerminalReciprocal

• Initial clicking : It is a sign of retruded condyle

• Intermediate clicking : Is a sign of unevenness of the condylar surfaces and articular disc

• Terminal clicking : is an effect of the condyle being moved too far anteriorly in relation to the disc on maximum jaw opening.

• Reciprocal clicking : is an expression of incoordination between displacement of the condyle & the disc.

MUSCLE EXAMINATION

MUSCLES PALPATED

TEMPORALIS MASSETER LATERAL PTERYGOID MEDIAL PTERYGOID

FUNCTIONALLY ASSESED

INFERIOR BELLY OF LATERAL PTERYGOID

SUPERIOR BELLY OF LATERAL PTERYGOID

MEDIAL PTERYGOID

TEMPORALIS

Anterior region – above the zygomatic arch & anterior to the TMJ

Middle – directly above the TMJ & superior to the zygomatic arch

Posterior – above & behind the ears

TEMPORALIS

With the index finger Palpate the cheek laterally at the Retromolar fossa.

INTRAORALLY

• MASSETER

Palpated bilaterally at its Superior and inferior attachments

Started anterior to TMJ and then dropped down to the inferior border of the ramus

MASSETER

Masseter (intra oral)

With the index finger intraorallyPress laterally inside the cheek.

• Palpation of Inferior lateral pterygoid should no longer be considered as a standard clinical procedure because it is nearly impossible to palpate it anatomically & also the risk of false +ve findings by palpation of the medial pterygoid muscle is high.

FUNCTIONAL ANALYSIS OF MUSCLES

• Lateral pterygoid• Medial pterygoid

• PrincipleA muscle which is fatigued & symptomatic elicits pain on further function and is painful both on contraction and stretching

Inferior belly of Lateral pterygoid

Contraction – mandibular protrusion, mouth opening or both

Stretching – maximum intercuspation of teeth

Differentiation test – place tongue blade in between posterior teeth. This prevents the teeth from reaching maximum intercuspal position. Hence lateral pterygoid does not stretch

Differential test – tongue blade is placed bilaterally & patient is asked to bite. This increases the pain if it is symptomatic while the stretching pain of inf. Belly of lateral Pterygoid is relievedStretching – also produces clenching

Differential test – patient is asked to open mouth widely. If pain is elicited it is from the elevator muscles

SUPERIOR BELLY OF LATERAL PTERYGOID

Medial pterygoid

Contraction – clenching

Differential test – tongue blade is placed bilaterally & patient is asked to bite. This increases the pain if it is symptomatic because elevators are still contracting.

Two dimensional imaging Panoromic radiographs Transcranial view Transpharyngeal view Transorbital view Reverse Towne’s view Submento-vertex (SMV) view Conventional tomography Arthrography

Three dimensional imaging Computed tomography (CT) Magnetic resonance imaging (MRI)

Panoramic view

Used as screening projectionProvides non corrected tomographic view of the condyles on one film

Transcranial projection - modified Schuller method

Provides sagittal view of lateral aspects of condyle and temporal component

Indication

Gross changes on the lateral aspect of jointDisplaced joint fracturesRange of motion

Transpharyngeal projection

Limitations Temporal components are not imaged well

IndicationsTo visualize gross erosive changes of the condyle

Provides sagittal view of the medial pole of the condyle

Transorbital projectionTransmaxillary, antero posterior view

Provides an anterior view of the TMJ perpendicular to the transcranial and transpharyngeal views

Indication It provides images of entire mediolateral dimension and the articular eminence , condylar neck and condylar head are imagedRange of motion cannot be assessedMainly for detection of condylar neck fractures

Reverse Towne’s viewSimilar to transorbital view

Useful for viewing medial displacements of the condyle

Submentovertex (SMV) projection

Provides view of the base of the skull with condyles superimposed on the condylar neck and rami

Conventional tomographyProvides the most definitive diagnostic information

about the osseous structures of the TMJ

Provides visualization of anatomic structures free from superimposition

Arthrography

Provides information regarding soft tissue of the joint

Technique – intra- articular administration of radio-opaque iodinated contrast agent is done under fluoroscopic guidance

After both the joint spaces are filled with the contrast agent the disk function is studied using fluoroscopy supplemented by tomography

Advantage – it is advantageous over MRI in identifying any perforations b/w the superior and inferior joint compartments

Disadvantages– 1. expensive

2. patient may develop allergy to contrast medium

3. invasive

Computed tomography

Incorporates the principles of direct digital (computed) electronic imaging & cross sectional radiography (tomography)

Provides visualization in all 3 planes

Sagittal (lateral)

Coronal (frontal)

Axial

Computed tomography

Magnetic resonance imaging (MRI)

Used to image soft tissues of the TMJ to visualizeJoint effusionDisk positionDisk shapeInflammatory changes

TEMPEROMANDIBULAR DISORDERS

• TMD – cluster of joint and muscle disorders in the

orofacial area characterized primarily by

– Pain

– Joint sound and

– Irregular or deviating jaw functions

Signs and symptoms of temporomandibular joint (TMJ) syndrome include pain in the jaw joint, clicking of the jaw, ear pain, popping sounds in ears, headaches, stiff or sore jaw muscles, pain in the temple area, or locking of the jaw

Epidemiology

• Epidemiologic studies has shown that 60-70% of the

general population have functional disturbances of

the masticatory apparatus.

• Its most prevalent between the ages of 20-40 years

and predominantly affects women.

Etiology

• Multifactorial– Parafunctional habits .– Emotional stress.– Acute trauma from blows / impacts.– Trauma from hyperextension.– Instability of maxillo-mandibular relationships. – Laxity of the joints.– Rheumatic / musculo-skeletal disorders. – Poor general health and unhealthy lifestyle.

Classification• Intracapsular disorders of the TMJ

Source DisorderDegenerative (non-inflammatory)

Degenerative joint disease

Inflammatory Rheumatoid arthritisPsoriatic arthritis

Infections Spread from contiguous site

Developmental Condylar hyperplasia, hypoplasia and agenesis

Traumatic Condylar fracture, ankylosis, dislocation and disc displacement.Burket’s

I. Developmental disturbances of the TMJ1. Aplasia of the mandibular condyle

– Condylar aplasia or failure of development of the mandibular condyle which may occur unilaterally or bilaterally.

– It is a rare condition

• Clinical features:– Associated with other anatomically related defects such as a

defective / absent external ear, an under developed mandibular ramus or macrostomia.

– Unilateral condylar aplasia Facial asymmetry– A shift of the mandible towards the affected side occurs during

opening– In bilateral cases this shift is not present

• Treatment– Osteoplasty– Orthodontic appliances– Cosmetic surgery in correcting facial deformity

2. Hypoplasia of the mandibular condyle– Under development / defective formation of the mandibular condyle

• Congenital hypoplasia– etiology could be Idiopathic – Characterized by uni / bilateral under-development of the condyle

• Acquired hypoplasia– May be due to any agent which interferes with the normal development of

the condyle.Causes:– Forceps deliveries – External trauma– X-ray radiation

• Clinical features:– Condylar hypoplasia depends upon whether the disturbance has affected

one or both condyles and upon the degree of malformation. – Age of the patient at the time of involvement– The duration of the injury and its severity – Unilateral involvement is the most common clinical type

– Facial asymmetry– Limitation of lateral excursion on one side – Mandibular midline shift during opening and closing– The distortion of the mandible results in lack of downward and

forward growth of the body of the mandible – Due to arrest of the chief growth center of the mandible i.e., condyle.

• Treatment & prognosis– Cartilage / bone transplants– Unilateral and bilateral osteotomy to improve the appearance of the

patient with asymmetry and retrusion.

3.Hyperplasia of the mandibular condyle– Condylar hyperplasia is a rare unilateral enlargement of the condyle Causes: Mild chronic inflammation which stimulates the growth of the

condyle or adjacent tissue.

Clinical features : patient usually exhibit A unilateral, slowly progressive elongation of the face with deviation of the chin away from the affected side. The enlarged condyle may be clinically evidentThe affected joint may or may not be painfulA severe malocclusion is a usual sequela of the condition

• Radiographic Features:– Condyle with an elongated neck and enlarged condylar

head – Scintigraphy using 99mTc-MDP used for assessing degree of

bone activity in condylar hyperplasia.

• Treatment and prognosis– If growth is occurring condylectomy – If growth is ceased orthognathic surgery is performed– Resection of condyle is done to restore normal occlusion.

Developmental disturbance of TMJ

Bifid condyle• Double headed mandibular condyle.• They have a medial and lateral head divided by A-P groove.• Some condyles may be divided into an anterior and posterior

head.

Etiology:Uncertain.A-P bifid condyle is mostly traumatic in origin.Mediolaterally divided condyles causes are trauma, abnormal muscle attachment, teratogenic agents.

Clinical Features:– Unilateral– Asymptomatic– Pop or click of TMJ

Radiographic Features:– Bilobed appearance of the

condylar head.

Rx & Prognosis:– Asymptomatic no treatment

necessary.

II. Traumatic disturbances of the TMJ

1. Luxation and subluxation (complete & incomplete dislocation)– Dislocation of the TMJ :when the head of the condyle moves

anteriorly over the articular eminence into such a position that cannot be returned voluntarily to its normal position.

– Luxation of the joint complete dislocation while subluxation is a partial / incomplete dislocation

• Clinical features:– Sudden locking and immobilization of the jaws when the mouth is

open. – Accompanied by prolonged spasmodic contraction of the temporal,

internal pterygoid and masseter muscles with protrusion of the jaw.

Treatment:Relaxation of the muscles and then guiding the head of the condyle under the articular eminence into its normal position by an inferior and posterior pressure of the thumbs in the mandibular molar area.

2. Ankylosis (hypomobility)– Most incapacitating of all diseases involving the TMJ.– It involves fusion of head of the condyle to the temporal bone.

• Etiology– Traumatic injuries– Infection in and about the joint– Abnormal intrauterine development– Birth injury– Trauma to the chin forcing the condyle against the glenoid fossa,

particularly with bleeding into the joint space.– Injuries associated with fracture of the molar zygomatic compound. – Congenital syphilis– Primary inflammation of the joint

– Inflammation of the joint secondary to a local inflammatory process. Ex. Otitis media; mastoiditis; osteomyelitis of the temporal bone / condyle.

– Inflammation of the joint secondary to a blood stream infectionEx: Septicemia

– Metastatic malignancies

• Clinical features:– Occurs at any age– Most cases occur before the age of 10 years– Distribution is equal between the genders– The patient may / may not be able to open his mouth to any

appreciable extent, depending on the type of ankylosis

• TMJ Ankylosis (depending on anatomic sites of ankylosis)

Intra-articular ankylosis Extra-articular ankylosis

Joint undergoes progressive destruction of the meniscus

Flattening of the mandibular fossa and. thickening of the head of the condyle & narrowing of the joint space

Results in a “splinting” of the TMJ by a fibrous or bony mass external to the joint proper

But movement is possible in this type

II. Traumatic disturbances of the TMJ

• Radiographic Features:– Reveals abnormal / irregular shape of the head of the

condyle• Treatment:

– Surgical osteotomy / removal of section of bone below the condyle.

– Fibrous ankylosis can be treated by functional methods.

III. Fractures of the condyle

Condylar fracture.

• Caused due to- Acute traumatic injury to the jaw

• SYMPTOMS- Limitation of motion, pain and swelling over the involved condyle

• Deformity is noted upon palpation and loss of normal condylar excursion.

• The fractured condyle fragment is frequently displaced anteriorly and medially into the infratemporal region because of the forward pull of the external pterygoid muscle and reduction of the fracture is often difficult because of this displacement.

• Healing of such fracture without reduction results in loss of function, limitation of motion or any other complication.

IV. INFLAMMATORY DISTURBANCES OF THE TMJ

• Arthritis / inflammation of the joints, is one of the most frequent pathological condition affecting the TMJ.

• TMJ may suffer from any form of arthritis but there are 3 common types given by Mayne and Hatch.– Arthritis due to a specific infection.– Rheumatoid arthritis.– Osteoarthritis / degenerative joint disease.

HISTOPATHOLOGIC FEATURES• There is a variable amount of destruction of the

articular cartilage and articular disk.• The joint spaces become obliterated in the healing

phase by the development of granulation tissue• It Subsequently transforms into scar tissue.

TREATMENT:• Antibiotics – in the acute phase

– Meniscetomy / condylectomy is advocated in the advanced cases.

2) Rheumatoid arthritis• Is a chronic multisystem disease of unknown antigen, triggers an

autoimmune response in genetically susceptible individual.• Proinflammatory kinins and cytokines play important role in pathogenesis

of rheumatoid arthritis.• TMJ involvement NEARLY 20%CLINICAL FEATURES:• M:F 2:1 Rheaumatoid Arthritis in early stages manifests as- • Slight fever.• Loss of weight• Fatigability.• Joints affected are swollen• Patient c/o pain and stiffness on movement of the jaw.• Ankylosis of the joint over a period of time.

Histopathologic features:• The joints show edema and inflammation of the synovial

tissues and diffuse infiltration of chronic inflammatory cells into the articular architecture.

• With increase in bone resorption there is a destruction of articular surface of the condyle.

• Invasion of the cartilage and its replacement by granulation tissue is seen.

Rx & Prognosis:• No specific treatment for Rheumatoid

Arthritis.• Administrations of Adrenocorticotrophic

hormone/ Cortisone.• Surgical intervention in the form of

condylectomy may be necessary to regain movement.

3. Osteoarthritis (degenerative joint disease, hypertrophic arthritis).

• Is most common type of arthritis associated with aging process.

Etiology: unknown.

CLINICAL FEATURES:• Signs and symptoms are absent since it is not a weight

bearing joint. • Patients c/o of clicking and snapping in the TMJ due to

atypical disk motion.

HISTOPATHOLOGIC FEATURES:• The cartilage cells often exhibit degeneration and areas of

dystrophic calcification may occur and this can progress to actual ossification ,also there may be necrosis of the disk.

Rx:• Condylectomy.

V. NEOPLASTIC DISTURBANCES OF THE TMJ

• Neoplasms and tumor-like growths, benign and malignant, may involve the TMJ.

• It is very uncommon.• Origin:• Within the bone of the mandibular condyle.• Joint capsule or articular disk.• Chondromas, osteomas and osteochondromas are

common benign tumors.

VI. EXTRA-ARTICULAR DISTURBANCES OF THE TMJ

• A variety of extraarticular disturbances may manifest themselves clinically as TMJ problems.– Impacted molar teeth– Sinusitis– Middle ear disease– Infratemporal cellulitis– Impingement of coronoid process on the tendon of the temporal

muscle.– Neuritis of the 3rd division of the trigeminal nerve.– Odontalgia.– A foreign body in the infratemporal fossa.– Overclosure of the mandible accompanied by severe dental attrition.– Costen’s syndrome.

VII. TEMPOROMANDIBULAR JOINT SYNDROME (TM disorder)

• TMJ syndrome or TMD is the most common cause of facial pain after toothache.

• TMD can be classified broadly as:– TMD secondary to myofacial pain and dysfunction (MPD).– TMD secondary to true articular disease

1. Myofacial pain disorder type forms the majority of the cases of Temperomandibular disorder and is associated with pain without apparent destructive changes of the TMJ on x-ray.

• Seen commonly in bruxism and day time jaw clenching in a stressed and anxious person.

DIGAMMATIC RERESENTATION OF ETIOLOGY OF MPDS

PSYCHOPHYSIOLOGIC THEORY OF MPDS(Modified by LASKIN in 1969)

2. True intra-articular disease :– Disk displacement disorder.– Chronic recurrent dislocations.– Degenerative joint disorders.– Systemic arthritis conditions– Ankylosis.– Infection– Neoplasms.

• Etiology:– Multifactorial and includes:– Malocclusion.– Jaw clenching.– Bruxism.– Personality disorders– Increased pain sensitivity.– Stress and anxiety.

Clinical features:– Affects young woman aged 20-40 yrs.– M:F – 1:4.– 4 cardinal signs and symptoms of the

syndrome:1. Pain2. Muscle tenderness.3. Clicking / popping noise in the TMJ.4. Limitations of the jaw motion unilaterally /

bilaterally with deviation on opening.– The pain is usually periauricular.– Associated with chewing and may radiate to

head.– May be unilateral or bilateral in MPD.

• In TMD, pain is associated with clicking, popping and snapping sounds.

• Limited jaw opening due to pain / disk displacement.• TMD acts as a trigger in patient prone to headaches.Lab findings:

– Blood examination.– Blood count– Rheumatoid factor– ESR– Antinuclear antibody.– Uric acid

• Treatment & Prognosis:1. Self limiting.2. Conservative treatment involving self care

practices.– Rehabilitation aimed at eliminating muscle

spasms.– Restoring correct coordination.3. Non steroidal anti inflammatory drugs. Eg:

Diclofenac sodium– Prognosis is usually good.

Use of Fixed orthodontics in tmd treatment

• Jco interview volume 1981 may (333-350)• Dr .eugene h. williamson on occlusion and tmj

function.• Dr williamson stated that in patients with dysfunction

there are two variables which always seem to be present. One variable is the abnormal emotional status of the patient, the other is the presence of prematurities or deflective tooth contacts

• It is important not to introduce splint dependency but to endeavour to resolve the occlusal imbalance related to tmd. successful treatment requires the reconstruction of functional occlusion with the condyle positioned correctly in the glenoid fossa.

• Depending on the etiology of the condition this may involve orthopaedic repositioning, orthodontic balancing of the occlusion , occlusal reconstruction or a combination of these disciplines.

.The treatment of tmd by interocclusal devices followed two paths: ( journal of oral

rehabilitation 2004)

Occlusal splints Functional orthopedic appliance

provide symptomatic relief

do not modify the occlusal discrepencies.

help in the movement of the teeth as well as the jaws to a musculoskeletally stable position

thus providing relief

• Orthodontic treatment should be carried out to achieve a functional occlusion which is in harmony with the craniofacial musculature.

• The finished cases should have the condyles as close to centric relation as possible, preferably with Centric relation coinciding with the Centric occlusion.

Orthodontic treatment by means of fixed and functional appliance bring about the movement of the teeth and jaws to a musculoskeletally stable position . Thus targeting one of the causative factors in temperomandibular disorders and hence providing a definitive therapy .

References

6. Shafer’s Textbook of Oral Pathology. 5th edition.7. Neville: Oral & Maxillofacial Pathology. 2nd edition.8. Jaffery P. Okeson – Management of

Temporomandibular disorders and occlusion.

1. Gray’s Anatomy2. Fundamentals of occlusion and TMJ disorders -- Okeson3. Grant’s Atlas of Human Anatomy4. Occlusion – Ash RamfJord5. Orthodontics Principles and Practice -- T.M.Graber

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