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What Causes TMD?


We know that severe injury to the jaw or temporomandibular joint can cause TMD. A heavy blow, for example, can fracture the bones of the joint or damage the disc, disrupting the smooth motion of the jaw and causing pain or locking. Arthritis in the jaw joint may also result from injury. Other causes of TMD are less clear. Some suggest, for example, that a bad bite (malocclusion) can trigger TMD, but recent research disputes that view. Orthodontic treatment, such as braces and the use of headgear, has also been blamed for some forms of TMD, but studies now show that this is unlikely.

And there is no scientific proof that gum chewing causes clicking sounds in the jaw joint, or that jaw clicking leads to serious TMJ problems. In fact, jaw clicking is fairly common in the general population. If there are no other symptoms, such as pain or locking, jaw clicking usually does not need treatment.

Researchers believe that most people with clicking or popping in the jaw joint likely have a displaced disc -- the soft, shock-absorbing disc is not in a normal position. As long as the displaced disc causes no pain or problems with jaw movement, no treatment is needed.

Some experts suggest that stress, either mental or physical, may cause or aggravate TMD. People with TMD often clench or grind their teeth at night, which can tire the jaw muscles and lead to pain. It is not clear, however, whether stress is the cause of the clenching/grinding and subsequent jaw pain, or the result of dealing with chronic jaw pain or dysfunction. Scientists are exploring how behavioral, psychological and physical factors may combine to cause TMD.