(See also Overview of Temporomandibular Disorders.)
Infection of the temporomandibular joint (TMJ) may result from direct extension of adjacent infection or hematogenous spread of bloodborne organisms (see Acute Infectious Arthritis). The joint area is inflamed, and jaw movement is limited and painful. Local signs of infection associated with evidence of a systemic disease or with an adjacent infection suggest the diagnosis. X-ray results are negative in the early stages but may show bone destruction later. If suppurative arthritis is suspected, the joint is aspirated to confirm the diagnosis and to identify the causative organism. Diagnosis must be made rapidly to prevent permanent joint damage.
Treatment includes antibiotics, proper hydration, pain control, and motion restriction. Parenteral penicillin G is the drug of choice until a specific bacteriologic diagnosis can be made on the basis of culture and sensitivity testing. For methicillin-resistant Staphylococcus aureus (MRSA) infections of the oral structures, IV vancomycin is the antibiotic of choice. Suppurative infections are aspirated or incised and drained. Once the infection is controlled, passive jaw-opening exercises help prevent scarring and limitation of motion.
Rarely, acute injury (eg, due to difficult tooth extraction or endotracheal intubation) may lead to arthritis of the TMJ. Pain, tenderness, and limitation of mandibular motion occur. Diagnosis is based primarily on history. X-ray results are negative except when intra-articular edema or hemorrhage widens the joint space. Treatment includes oral corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs), application of heat, a soft diet, and restriction of jaw movement.
The TMJ may be affected by osteoarthritis (degenerative joint disease), usually in people > 50 years. Occasionally, patients complain of stiffness, grating, or mild pain. Crepitus may result from disk degeneration or perforation, causing bone to grate on bone. Joint involvement is generally bilateral. X-rays or cone beam CT may show flattening and lipping of the condyle, suggestive of dysfunctional change, most likely due to excessive loading of the joint. Treatment is symptomatic. An oral appliance (mouth guard) worn during sleep (and possibly while awake) may help alleviate pain and reduce grating sounds.
This arthritis usually develops in people (usually women) aged 20 to 40 years with a history of trauma or persistent myofascial pain syndrome. It is characterized by limited opening of the mouth, unilateral pain during jaw movement, joint tenderness, and crepitus. When it is associated with myofascial pain syndrome, symptoms wax and wane.
Unilateral joint involvement helps distinguish secondary degenerative arthritis from osteoarthritis. Diagnosis is based on x-rays, which, as in osteoarthritis, generally show condylar flattening, lipping, spurring, or erosion.
Treatment is conservative, as it is for myofascial pain syndrome, although arthroplasty or high condylectomy may be necessary. An oral appliance (occlusal splint [mouth guard]) usually relieves symptoms. The appliance is worn constantly, except during meals, oral hygiene, and appliance cleaning. When symptoms resolve, the length of time that the appliance is worn each day is gradually reduced. Intra-articular injection of corticosteroids may relieve symptoms but may harm the joint if repeated often.
The TMJ is affected in > 17% of adults and children with rheumatoid arthritis, but it is usually among the last joints involved. Pain, swelling, and limited movement are the most common findings. In children, destruction of the condyle results in mandibular growth disturbance and facial deformity. Ankylosis may follow. X-rays of the TMJ are usually negative in early stages but often show late-stage bone destruction, which may result in an anterior open-bite malocclusion. The diagnosis is suggested by TMJ inflammation associated with polyarthritis and is confirmed by other findings typical of the disease.
Treatment is similar to that of rheumatoid arthritis in other joints. In the acute stage, nonsteroidal anti-inflammatory (NSAID) drugs may be given, and jaw function should be restricted. An oral appliance worn during sleep is often helpful. When symptoms subside, mild jaw exercises help prevent excessive loss of mandibular motion. Surgery is necessary if ankylosis develops but should not be done until the condition is quiescent.