Temporomandibular Joint Disorder (TMJ Disorder)

The temporomandibular joint (TMJ) is one of the most complex joints in the body. Comprised of several muscles, ligaments and bones, the joint contains a disc between a ball and socket, with the disc cushioning the forces on the joint that enable jaw movement and function. When any of these parts are not functioning properly, a temporomandibular joint disorder (TMD, TMJD) could develop.

TMD is a condition affecting the temporomandibular joint, jaw muscles and nerves on one or both sides of the head that causes jaw, face, and head and neck pain. The most common symptom associated with TMJ disorder is a painful sensation in the chewing muscles or jaw joint. This pain and discomfort may be severe, intermittent or continuous, and may last for several years. A frequent pain or soreness in the jaw which is more prevalent in the morning and afternoon, difficulty opening and closing the mouth and/or chewing, clicking or popping when opening/closing the mouth, swelling on the side of the face, and frequently waking up with headaches or frequent tension headaches, are other symptoms related to TMJ disorder.

Causes of TMJ Disorder

An estimated 10 million people are affected by TMJ disorder. While trauma to the jaw or jaw joint, such as a jolting injury to the head, face or neck, could contribute to TMD, most cases do not have a definitive cause.

The most common contributing factor to TMD is a bad bite (malocclusion) that affects the joint. For example, any irregularity in the structure of individual teeth may cause the lower jaw to dislocate and force the muscles moving the joints out of their sockets. Wear and tear on the teeth caused by aging, teeth grinding and clenching, or abnormal function may cause uneven surfaces on the teeth that lead to an improper jaw closure.

Some TMJ disorders are caused by arthritis and displacement, while other cases may result from disease or a genetic predisposition to TMDs. Anatomical factors within the joint or surrounding muscles, such as the presence of scar tissue, also may interfere with the bite and cause TMJ disorder.

Diagnosing TMJ Disorder

In most cases, your dentist can diagnose and treat TMJ disorder. Diagnosing TMD prior to treatment is essential, even though currently there is no universal standard test to identify all TMD conditions.

The diagnosis of TMJ disorder begins with a comprehensive oral health examination consisting of an assessment of joint and muscle tenderness, clicking and popping, and ease of movement. Your dentist also may perform a "clench test" in order to understand the nature of your pain. X-rays and impressions of your upper and lower teeth also are taken so that cast models can be made to study the jaw-to-bite relationship and the position/condition of your temporomandibular joint.

Your dentist can measure forces on the teeth, proper balance of the bite and timing of the bite using a specialized computer bite analysis test (T-scan). This test can help to determine if a structural disorder exists within the joint itself, or if interferences in the bite are affecting the joint's ability to close properly.

Treatments for TMJ Disorder

A variety of treatment alternatives are available to treat TMJ disorder. Most dentists are qualified to evaluate jaw-to-bite relationships and familiar with proper treatment procedures, such as occlusal equilibration and the use of mouth guards, splints and other appliances. Orthodontics may be able to improve occlusion and treat TMJ.

When treating TMJ disorders, "conservative" is the key. For severe cases, splints, mouth guards and other traditional forms of TMD therapy may be necessary. Surgery is only considered after attempting all other conservative treatment options, since it may not resolve TMD problems. Following your dentist's directions for the prescribed treatment is crucial.

Alternative TMJ disorder treatments include transcutaneous electrical nerve stimulation (TENS), ultrasound, trigger-point injections and radio wave therapy. These methods use low levels of electrical or radio waves of energy to stimulate blood flow to the joint and surrounding area. These options don't treat causes of TMD, but they may provide temporary relief.

The cost for treating TMD is based on the expertise and location of the dentist, the type of dental insurance you have and facility fees for procedures, if any.