Orofacial pain is the presenting symptom of a broad spectrum of diseases. Some of these disorders are easily recognized and treated whereas others defy classification and are unresponsive to present treatment methods. The possible causes of orofacial pain are considerable and cross the boundaries of many medical and dental disciplines. As a symptom, it may be due to disease of the orofacial structures, generalized musculoskeletal or rheumatic disease, peripheral or central nervous system disease, or psychological abnormality; or the pain may be referred from other sources (e.g., cervical...