Tempromandibular Joint Ankylosis

• Etiology, Signs and symptoms, Differential diagnosis, Radiographioc examination, Treatment

Tempromandibular Joint Arthiritis

• Classification, Degenerative arthiritis, Traumatic arthiritis, Other forms of arthiritis

Functional Disorders of Tempromandibular Joint

• Clicking, MPD, Dislocation

LINKS

By definition, Ankylosis is the inability of a joint to perform its full function. Ankylosis of the TMJ, when occurs early in life will affect the mandibular growth causing facial assymetry. This is because function plays an important role in growth of the mandible.

Ankylosis of TMJ is classified into bony ankylosis and fibrous ankylosis as well as intraarticular or true ankylosis and extraarticular or false ankylosis.

In cases of fibrous ankylosis fibrous tissues obliterates the joint cavity and the articular surfaces of the joint are connected by vascularised connective tissue. The articular cartilage is destroyed. By time the fibrous connective tissues become calcified ane the partially destroyed condyle becomes attached to the base of the skull. Wide spread ossification usually occurs attaching the condyle to the temporal bone and also the zygomatic arch in sever cases.

I. Extra-articular (False) Ankylosis

Muscular trismus: Usually due to infection. This is common with pericoronitis, submastric abscess, and pterygomandibular space abscess.

Muscular atrophy of fibrosis: This may be due to myositis ossificans, submucous fibrosis or other similar conditions.

Tetany and Tetanus: Tetany is seen in hypocalcimia while tetanus is an acute infection caused by “Colstridium Tetani” and cause presistant tetanic spasm of some of the voluntery muscles. One of its early symptoms is lock jaw.

Neurogenis closure: As in nerveousness, eplipsy and brain tumors.

Trismus histricus: Usually occur following acute fright.

Mechanical lock: As in cases of bony exstosis or osteomas of the coronoid process and in some cases of zygomatic arch and coronoid process fracture where the diplcaed segment of bone mechanically prevent the normal mandibular opening.

II. Intra-articular (True) Ankylosis

Birth trauma: This will result in infantile ankylosis and it occurs with difficult deliveries and often associated with other bone fractures.

Trauma: Trauma is responsible for more than 30% of cases of acquired ankylosis. Fracutre of the condyle may cause ankylosis which may be due to intra- or extra- articular hemorrhage. This will result in hematoma formation which may be organized and calcified.

Rheumatoid arthritis: All types of arthritis may end in ankylosis.

Infection: Inflammation of the joint due to direct extension of infection from the surrounding tissue may result in ankylosis. Infection may reach the joint from ear infection dental infection or may be a blood born infection.

• Inability to open the mouth: There is gradual inability to open the mouth with difficulties or inability to masticate. Usually there is some degree of movement even with the most sever types of anylosis which is due to the elasticity of the mandible and the movement that takes place at the cranial sutures.

• Deviation of the midline: In unilateral ankylosis some degree of mandibular movement is possible with deviation of the mandible to the affected side.

• Pain: Pain is not a symptom and it may be present only in the early stages of the diseases that produce the ankylosis.

• Facial defomaties: There will be facial asymmetry in unilateral cases. The mandible will appeare deviated toward the affected side. In bilateral cases ther are:

• Receeding chin due to lack of normal growth of the mandible. This tupe of deformity gives the patient the cahracteristic “Bird face appearance”. The condition id more obvious when ankylosis occurred early in life.
• The is malocclusion and bad oral hygine.
• Accentuated antigonial notch due to the action of the muscles on the ankylosed mandible.
• Curvature of the inferior border of the mandible due to the action of the depressor muscles attached to the symphsis.

Intra-articular and extra-articular ankylosis can be differentiated by asking the patient to protrude the mandible. Gliding movement is possible in cases of extra-articular ankylosis as the joint cavity is not affected.

Panoramic radiographs, TMJ tomography in open and closed positions as well as CT scans are all used in examination of TMJ disorders.

• Panoramic radiograph will give a general picture for the temporomandibular joint region.
• TMJ tomography is useful for the examination of the range of movement of the joint, both hing and gliding, as well as the joint cavities.
• CT scans if very helpful to detect the exact extension of the bony ankylosis in all direction.
• MRI is used to examine the disc and any abnormalities in it.

Treatment of ankylosis should be performed as early as possible to give chance for the mandibular growth to take place. Ankylosis more easily to be prevented than treated. Prevention of ankylosis include proper treatment of all mandibular trauma and infections in and arround the joint. When the patient notice any abnormality in the mouth opening he should seek the advise of the oral surgeon to start physiotherapy and perform muscular exercises.

False ankylosis is managed by treating the underlaying cause. On the other hand true ankylosis either fibrous or bony is treated by arthrolyisi, osteoartherotomy or condylectomy.

Arthrolysis: Is used in case of fibrous ankylosis and consists of breaking done of the fibrous tissues by forced opening of the mandible while the patient under general anaesthesia or surgically.

Osteoarthrotomy: Creation of an artificial joint space (pesudoarthrosis) which is used in case of complete bony ankylosis and condylar tumors.

Condylectomy: Removal of the condyle is used in cases of sever arthrosis and fibrous ankylosis.

Arthroplasty: After creation of an artifical joint space arthroplasty aim to prevent the reunion of the bony fragments.

•    Replacement of the condyle: The condyle may be replaced by bone, transplantation of digital phalynx or by alloplastic material.
•    Interpositioning arthroplasty: A forigen material is used to prevent the recurrence of the ankylosis. However, it has been reported by many investigators that the need for interpositioning of forigen materials, either autogenous as muscles, facsia and cartilage or alloplastic as titanium and vitalium, is very limited providing that enough bone has been removed and adequate postoperative excercises has been established.

Arthritis is an inflammatory or degenerative reversible disease involving the joints and characterized by pain, stifness and decreased range of motion.

Classifications

• Degerative Arthritis: Non-inflammatory degenrative disease charaterized by abrasion of the articular soft tissue surfaces and remodelling process in the underlaying bone. It involves mainly the articular hyaline cartilage.

• Traumatic Arthritis: It may result from acute heavy trauma or repeated chronic microtrauma imposed on the joint.

• Rheumatoid Arthritis: It is a progressive systemic disease that affects the joint of the hand and ankles. The joints are affected symmetrically and the TMJ may be involved.

• Infective Arthritis: The TMJ as any other joint may be the site of specific infectious arthritis bu this is not common.

• Arthritis associated with metabolic abnormalitis: Arthritic changes usually develop as a result of deposition of microcrystals in the joint tissues. For example "Arthritis Urica" which occurs with Gout due to deposition of uric acid in the joint.

DEGENERATIVE ARTHIRITIS

This is a non-inflammatory degenerative disease characterized by abrasion of the articular soft tissues surfaces and remodelling process on the underlaying bone. It involves mainly the articular hayline cartilage. The condition also termed osteoarthrosis, arthriosis deformans and hypertrophic arthitis.

Incidance:

The disease is common in the middle and old age group. It is thought to occur more in females, but the exact incidence is difficult to determine because in many cases the disease is symptomless.

Etiology:

The exact etiology is not well known however many factors have been suggested.

• Senelity: The common occurance of the disesease in old age indicates that the functional capacity of the joint declines with age. In such case it is called primary osteoarthrosis.

• Increased mechanical loading of the joint: When the functional capacity of the joint is exceeded by overload, degenerative rather than physiological changes will take place. Overloading of the TMJ may be due to posterior overclosure as in cases of loss of posterior teeth, prafunctional habits, micro or macro trauma, malocclusion and excessive chewing of hard food.

• Genetic suscieptibility: Some peaople have genetic predisposition to osteoarthrosis, i.e. they have lower level of collagen in the superficial zone of the articular surfaces and thus their resistance to stress is below average.

Signs And Symptoms

• Pain and tenerness on movement and on palpation.
• Joint nosie as grinding or crushing nosie, bu not clicking.
• Limitation of mandibular opening.
• Deviation to the affected side in unilateral cases.
• Locking of the joint may occur in some cases.
• Ear ache, dizziness and headache.
• In sever cases there may be shortening in the total length of the condyle due to repeated remodelling which may lead to facial asymmetery in unilateral cases.

Radiographic Finding

Radiographic findings is the base for diagnosis of degenerative arthritis. Usually at the early stages of the disease there is no radiographic findings. Two to four months after the beging of the symptoms radiographic evidence of degeneration is seen. These changes include the following:

• Changes in the joint space: The joint space is reduced which indicates loss of the articular cartilage and/or perforation of the disc.
• Changes in the eminance: The posterior slope of the eminance may be flattened or hollowed and the eminance may even worn down.
• Changes in the condyle: These include flattening of the articular surface, localized depresion or cyst like erosion, marginal lipping and sclerosis of the subchondral bone. The condyle may be weakened to the extent that it becomes flat, compressed and bent.

Treatment

Treatment of degenerative arthritis may be conservative or surgical. Conservative treatment include reduction of the overload by restoration of occlusion, physiotherapy in the form of heat aplication and theraputic exercises and drug therapy by admenistration of analgesics and steroids as an antiinflammatory drugs.

The surgical treatement, high condylar shave, subcondylar osteotomy or condylectomy, uis used in advanced cases.

TRAUMATIC ARTHIRITIS

Arthritis may occur as a result of acute heavy trauma or chronic repeated microtrauma, e,g, traumatic occlusion. Diagnosis of traumatic arthiritis is based on the presence of the following clinical features:

• Through history taking the patient sate a normal joint function before injury.
• Continuity of joint symptom from the time of trauma.
• The traumatized joint is the only joint affected.
• The trauma should be sever enough to cause synovitis, pain, swelling and dysfunction.
• Progressive articular changes that are detectable radiographically 3-6 months after the trauma.

Effect Of Acute Trauma

1. Capsulitis and synovitis: There will be swelling and tenderness of the joint together with restriction of movement and simetimes acute malocclusion. This is due to collection of the inflammatory exudate in the joint.

2. Retrodiscuitis: Truama that tends to push the condyle posteriorly may stimulate inflammation of the retrodical loose areolar connective tissues which is accompanied by pain and swelling within the joint as well as limitation of function. The inflammatory exudate and the engarged retrodiscal tissues may push the condyle anterorly.

Clinically there will be disocclusion of the isilateral posterior teeth and premature contact of the contralateral anterior teeth. There is also pain on bitting hard opjects. Radiographically the condyle is seen displaced anteriorly in rest position. treatment Maintaince of occlusion which may necessitate intermaxillary fixation for short period. Gentel gradual movement should be encourged.

3. Elongation Or Tears O Collateral Ligmant: The collateral ligmant, which attach the disc to the medial and lateral poles of the condyle, when elongated or teared it will result in:

• Invagination of the capsule into the joint cavity.
• Displacement of the disc by the pull of the lateral pterygoid muscle.
• Incoordiation of the movement of the disc with the condyle which result in irrugular noisy rough movement.

Clinically there will be pain and clicking on mustication due to anterior displacement of the disc at the end of closing by the action of the lateral ptrygoid muscle. Pain and closing may also occur at wide opening due to posterior displacement of the disc by the action of the retrodiscal lamina. Treatment includes the use of occlusal splints, scleosing agents, intermaxillary fixation for 10-14 days after trauma and surgery if symptoms presist.

4. Disc Compresion And/Or Perforation: Considering that the disc is the most avscular piece of tissues in the entire body, it is common to get disc perforation and/or necrosis following trauma. This will alter the joint function through:

• Prtrousion of the condylar head through the perforation in the disc.
• Pain dus to bone to bone contact of the articular surfaces.
• Clicking, pain and dysfunction of the joint movement.

5. Disc Adhesion: The hematoma formed as a result of trauma may undergo fibrosis. Fibrous tissues may be depositied in the lower compartment of teh joint joing the disc to the condyle.This will prevent the normal rotoatory movement between the disc and the condyle so ther will be pain at the beging of opening.

OTHER FORMS OF ARTHIRITIS

1. Rheumatoid Arthritis:

Rheumatoid arthritis is a progressive systemic disease characterized by inflammation of the joints. The exact etiology of the disease is unknown but it has be suggested to be an autoimmune disease or a collagen disease affecting the synovial collagen. The disease affects usually middle age people and females are more affected than males. More than 50% or cases show temporomandibular joint involvement.

Clinically:

• Usually symptoms of other joints sadow those of the temporomandibular joint.
• The course of the disase is unpredictable, repeated remmision and excerbation are common.
• There is pain and swelling with morning stiffness and limitation of mouth opening.
• Subluxation may occur.
• Anterior open bite if occured it indicates complete condylar distruction.
• Ankylosi may be the end result.

Radiographically:Radiographic changes occur late but are progressive. Reduced mobility, reduction of the joint space, surface errosions, flatting or lippig of the condyle are all a common radiographic findings. Specific for the rheumatoid arthritis is the presence of irrigular distruction of the joint compartments especially the articular tubercle.

2. Infectious Arthritis

The infection may reach the joint either by diorect spread from a present infection, peneterating wound or may be blood borne infection.

Clinically:

• Acute onset with sever pain at rest and function.
• Fever with swelling and tenderness of the joint.
• Accumulation of the inflammatory exudate in the joint space may cause anterior and dowonward displacement of the condyle which result in disocclusion of the ipsilateral posterior teeth.
• Distruction of the articular surfaces may occur.
• Ankylosis may be the end result.

3. Metabolic Arthiritis

arthritic changes as a result of deposition of micocrystals in the joint may occur in the following cases:

• Arthritic Urica: This form of arthritis is associated with gout where there is deposition of micrpcrystals of sodium ureates in the joint cartilage which occur secondary to the elevation of the uric acid level in the blood.
• Chondrocalcinosis Articularis (Pesudogout): Characterized by deposition of calcium pyrophosphate dihydrate in the disc and joint cartilages. It occurs with hyperparathyrodim and diabetes millitus.

CLICKING

Clicking in the TMJ is an annoying and even alarming symptom. There is disagreement concerning its etiology. However, there are two general concepts:

• Disorders in the meniscus proper: Which include loose articular cartilage, bending and straightening of the meniscus and roughening of the meniscus due to pathological condition.

• Muscles incoordination: Clicking is due to displacement of the meniscus due to over action or irregular action of the external peterygoid muscle. As the disc is attached anteriorly to the lateral pterygoid muscle and has a loose attachment to the capsule posteriorly, incoordination of the lateral pterygoid muscle during mandibular opening or closing may result in the following:

• The disc may be held in place while the mandible is displaced posteriorly.
• The mandible is stabilized while the disc is displaced anteriorly
• In most cases a combination of the two possibilities occur.

Signs And Symptoms

• Clicking is more common in young persons.
• May disappear spontaneously without recurrence or reappear on the other side.
• During physical examination clicking may disappear.
• Some people can voluntary induce clicking by deliberating incoordination of the muscles. Others can voluntary eliminate clicking by deliberating muscle coordination.

Treatment

Clicking is a benign symptom and has no serious complication. Accordingly it should not be treated aggressively except in the following cases:

• Patients in whom clicking is so audible to others.
• Patients in whom clicking is followed by painful limitation of mandibular opening.
• Patients in whom anxiety is so great that they continue to be disturbed by the symptom.

Many procedures are of value in the treatment of clicking this include exercises, physiological rehabilitation, occlusal adjustment, high condylectomy and condylectomy in sever cases.

MYOFACIAL PAIN DYSFUNCTION SYNDROME (MPD)

This condition is a functional disorder of the temporomandibular joint that is characterized by discomfort in the oral and para-oral region with mandibular movement. Usually it comprises a combination of muscular pain and mandibular dysfunction.

Incidence:

It was thought that the condition occur more in females between 30-50 years of age, however recently it was reported that there is no sex predilection, but females usually seek treatment more than males.

Signs And Symptoms:

• Pain: The pain is dull and unilateral, which may be intense in the morning or may be minimal and increase during day. The site of pain may range from the back of the head and neck posteriorly to the temporal era superiorly and the angle of the mandible anteriorly.

• Tenderness of the masticatory and related muscles: Palpation of the masticatory muscles and related muscles will reveal the presence of painful areas which represent a spasmodic part of the muscle which is capable of referring pain to remote areas. For example pain in the temporalis muscle may be referred to the maxillary dentation and pain in the masseter may be referred to posterior teeth and ear region.

• Clicking: However, clicking alone is not diagnostic for MPD, but if accompanied by pain and muscle tenderness it is diagnostic.

• Limitation of mandibular movement: Usually there is some limitation in mandibular movement, opening, closing and lateral movement.

• Lack of evidence of organic changes in the TMJ and no tenderness on palpation of the joint. This two finding are diagnostic.

Etiology:

The condition is multifactorial, however, the spasm of the masticatory muscles is the primary cause for the pain and mandibular dysfunction. There are two theories regarding the cause of the myospasm which are:

• Occlusal disharmony: The myospasm is due to the disharmony between the position of the condyle and the dental occlusion. Normally in centric occlusion position the condyle is centrally placed in the fossa, abnormal condylar position may be caused by malocclusion, burxism, premature contact and loss of posterior teeth. This theory is supported by the common presence of para-habits as clenching in patients suffering from MPD and the improvement which occur after occlusal adjustment.

• Psychological stress: Patient response to stress is the main factor and occlusal disharmony acts as a trigger in patients spychologically predisposed. Response to stress may be in the form of increased muscle tension including masticatory muscles. Usually there is barafunctional habits as clenching and grinding of teeth. In favor to this concept is the following:

• Hyperactivity of the jaw muscles is initiated centrally by the environmental stresses.
• MPD,s patients shows generalized skeletal muscle hyperactivity.
• Many MPDs patients either having or had had other spychological predisposed diseases as peptic ulcer and migraine.
• High percentage of positive results obtained with the use of placebo drugs and placebo splints.

Treatment:

The syndrome is basically a myoskeletal disorder. Dysfunction is sue to excessive muscular activity which leads to injury to the TMJ, dental apparatus and the muscles themselves. This in turn result in degenerative changes in the TMJ. The objectives of treatment of MPD are:

• Control pain and discomfort.
• Elimination of occlusal disharmony.
• Lowering the psychological stress or tension.

Limitation of jaw movement: This line of treatment provides rest of the masticatory muscles for 2-3 weeks. Immobilization may be performed by the use of wires and splints, but best to performed voluntarily by the patient following liquid and soft diet regimen.

Occlusal adjustment: This is done to maintain and improve the muscle equilibrium and coordination and in turn the joint function.

Splints and occlusal bit planes: It has the advantage of eliminating the occlusal interference and provides a stable position of the teeth during movement. Also it minimize the effect of the teeth in bruxism.

Thermotherapy: Heat application leads to vasodilatation and washing of the noxious metabolic products which accumulate in the muscles due to the sustained state of contraction. Also heat application has muscle relaxant effect and counterirritant effect which aid in elimination of the painful stimuli.

Muscular exercises: Also has muscle relaxant effect and reestablish muscular coordination.

Muscle relaxants therapy: The aim is to relief muscular spasm to interrupt the pain-spasm-pain cycle

Spychological therapy: The aim to decrease muscular spasm and increase the patient adaptive response to treatment .

Intramuscular injection of local anaesthesia: This technique is used to confirm the diagnosis and to provide a pain free period for the muscle exercises.

DISLOCATION

Dislocation is the displacement of the condyle out of the glenoid fossa where it is held anteriorly and superior to the summit of the articular eminence, but within the capsule of the joint. On the other hand

The condyle most commonly become displaced anteriorly to be held anterior and superior to the eminence. In rare occasion, usually due to sever trauma, the condyle may be displaced posteriorly cracking the tympanic plate or superiorly to be impacted in the middle cranial fossa.

Etiology:

• Extreme trauma.
• Sudden wide mandibular opening as in yawing.
• Prolonged wide opening.
• Capsular laxity as with chronic subluxation.

Signs And Symptoms:

• The mouth is opened and rigidly set in position with the chin protruded.
• Chin is tilted to the nonaffected side in unilateral cases.
• In ability to close the mouth.
• There is usually sever pain.
• By palpation a depression is found anterior to the ear, anterior to which there is an elevation indicating the displaced condyle.

Types Of Dislocation:

Acute dislocation: It usually occurs after sudden stretching of the masticatory muscles as in yawing or wide opening.

Recurrent dislocation: This term is used when the dislocation of the condyle occurs several times with inability of the patient to reduce it by himself.

Subluxation: This is a term used for lack of a better term to identify a condition described by the patient as the patient as the jaw momentarily lock, slip or going out of place with the bite off. Some authors describe subluxation as self-reducable dislocation.

Mechanism Of Dislocation:

Usually the condyle and the disc passes the anterior slope of the articular tubercle when the mouth is fully opened. Dislocation occurred while the condyle is in this position is due to faulty muscular coordination. When, at the beginning of the closing movement, the lateral pterygoid muscle remain contracted instead of relaxing, the elevator muscles will exert their force while the condyle is still on or anterior to the height of the articular tubercle. Dislocation is thus unavoidable.

Treatment:

I. Manual Reduction: Manual reduction is used in cases of acute or recurrent dislocation to set the displaced condyle back into the glenoid fossa. The operator stands infront of the patient with the thumbs on the molar region. The mandible is pressed downward and backwards. Reduction is facilitated by applying topical anaesthesetic spray to the region of elevator muscles during reduction. After reduction four-tailed bandage is applied and the patient is instructed to restrict the mandibular opening for 48 hours.

Another technique for reduction of the displaced condyles is by standing behind the patient, stabilizing the patient’s head by your abdomen. The mandible is rotated in the same direction by pressing on the mandibule proper rather than the occlusal plane.

II. To Prevent Recurrent Dislocation:

Immobilization: The aim is to keep the joint at rest for a considerable period of time to avoid extreme movements. This will give time to loose ligament to recover. This method, however, interfere with function and has an unpleasant spychological effect on the patient.

Surgical methods: This include:

• Eminoplasty: Reduction of the height of the articular eminence will facilitate self reduction of the condyle.
• Capsular tightening: Surgical tightening of the lux ligament of the capsule will prevent the anterior displacement of the condyle.
• Condylectomy: Removal of the entire condyle is used as a final resort in sever unresponsive cases.