Temporomandibular syndrome is a catch-all term for conditions that cause dysfunction or pain in the jaw joint and the surrounding face. The temporomandibular joint (TMJ), the muscles of mastication (chewing), the associated connective tissues, or all of these structures may be involved.
The TMJ is a classic “ball-and-socket” joint. The mandibular condyle forms the ball; the socket is formed by the glenoid fossa, which is a hollow at the base of the cheekbone; a cartilaginous articular disk forms a cushion between the condyle and the roof of the fossa. This disk is donut-shaped with a tough membrane stretched over its hole.
Diagnosis of TMJ Syndrome
Several conditions can mimic TMJ syndrome, including sinusitis, toothache, trigeminal neuralgia, post-herpetic neuralgia, otitis media (ear infection), or temporal arteritis. These conditions must be ruled out before a diagnosis of TMJ syndrome is made.
Pain that is worsened by finger pressure on the TMJ when the mouth is open implicates the joint. Auscultation or palpation over the joint during repeated opening and closing of the mouth may reveal popping, grinding, clicking, or catching. Observation of the jaw with opening and closing may reveal deviation of the mandible toward the affected side.
X-rays or MRI may be needed to further evaluate TMJ pathology.
Causes and Treatment of TMJ Syndrome
- Ankylosis: Fusion of the TMJ is most often the result of trauma, but can be due to rheumatoid arthritis or infection. Normal bony architecture is lost. Surgical removal of the condyle and part of the surrounding bone may be necessary. Post-surgical jaw-opening exercises must be performed for months to years.
- Arthritis: Joint inflammation due to infection, osteo- or rheumatoid arthritis, or trauma can cause TMJ dysfunction. Treatment may include antibiotics or surgical drainage (for infectious arthritis), pain medications, non-steroidal anti-inflammatory drugs (NSAIDs), application of heat or ice, soft diet, night guards or splints, mild jaw-opening exercises, and treatment of underlying conditions (i.e., rheumatoid arthritis).
- Bruxism (clenching or grinding of teeth): Usually occurring at night, bruxism can place extraordinary or imbalanced stress on one or both TMJs. Conscious avoidance of grinding during the day is recommended; mouth guards are worn at night to reduce mandibular pressures. Short courses of mild sedatives may help.
- Missing teeth or malocclusion: Unbalanced jaw motion during chewing can lead to uneven TMJ pressures; eventually, degenerative changes and arthritis result. Selective grinding of teeth, bracing, overlays and restorations will alleviate the underlying condition. TMJ dysfunction can then be addressed as for “arthritis” above.
- Persistent gum chewing: Chronic chewing imbalance and uneven TMJ pressures can eventually lead to arthritic changes. Cessation of gum chewing, a soft diet, gentle exercises, heat or ice, and NSAIDs will usually alleviate symptoms.
- Abnormalities of condylar growth: The mandibular condyle occasionally exhibits over- or undergrowth due to trauma, infection, or irradiation to the face. This leads to mandibular asymmetry and malocclusion; TMJ surgery is usually indicated.
- Internal joint derangement: Abnormal jaw mechanics may pull the articular disk out of its usual location, leading to TMJ syndrome. Treatment with jaw rest, pain medications, splints, and physical therapy usually help. Surgery may be necessary if conservative management fails.
- Myofascial pain syndrome: Spasm, pain, and tenderness of the muscles around the TMJ are common complaints. Bite splints, pain medications, habit modification, soft diet, and muscle relaxants are usually effective. Botulinum toxin has been used to relieve muscle spasm in some cases.
TMJ syndrome is a troublesome and sometimes chronic condition. Lifestyle changes will alleviate many of its symptoms, but medications, physical therapy, oral appliances, and even surgery may be required to attain relief.
Resource: The Merck Manual, Eighteenth Edition, 2006:849-51;861-866
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