Five years ago, Stephen, a 40-year-old business manager, started having occasional pain in his jaw and the muscles of his face and neck. Sometimes he would have trouble moving his jaw and would hear clicking sounds while he was chewing. His doctor and dentist told him to reduce the stress in his life and make sure he was not clenching his teeth. Despite his best efforts, the symptoms got so bad that his work performance suffered. Another doctor suggested he see a dentist who had experience treating orofacial pain. This dentist diagnosed Steve's problem as a temporomandibular disorder (TMD) and recommended a combination of treatments that finally relieved his pain and chewing difficulties.

There has been a great deal of controversy among clinicians and researchers about the name, definition, symptoms, causes, and treatment of temporomandibular disorders. As a result, many people with TMD have gone to several medical and dental providers before getting a correct diagnosis and treatment.

The temporomandibular joint (TMJ) is the jaw joint. Temporomandibular disorders (TMD) refers to a group of conditions that affect the temporomandibular joint, as well as the muscles that control chewing. Although the terms "TMJ" and "TMJ disorder" are sometimes still used to describe disorders associated with this joint, "TMD" is becoming the accepted term.

Because of a lack of agreement about these disorders, we do not really know how many people have TMD. For most people, the discomfort is temporary and fluctuates over time. Only a small percentage develop serious, long-term problems. TMD appears to affect women more than men.