TMJD is a heterogeneous family of musculoskeletal disorders associated with the temporomandibular joint, the periauricular region, and the muscles of the head and neck. TMJD has been identified as a major cause of nondental, chronic pain in the craniofacial region, second only to headache (NIH Technology Assessment Conference, 1997). Although few population-based epidemiological studies have been conducted, studies report the prevalence of TMJD as up to 20% in the adult population (Dworkin et al 1990, Schiffman et al 1990). Dworkin and colleagues conducted a series of studies of TMJD using valid and reliable examination and survey procedures (Von Korff et al 1988, Dworkin et al 1990, Carlsson and LeResche 1995) and identified 12.1% of the test population with painful TMJD with a female to male ratio of approximately 7:1. They also found the annual incidence of developing TMJD to be just over 2% with females tending to show a higher incidence rate than males (Von Korff et al 1993). Hence, TMJD is common in the general population, but it has also been reported that about 20% of patients with early signs and symptoms of TMJD will progress to a persistent pain state (Schiffman et al 1990).