Patients between the ages of 18 and 65 years with painful jaw joint conditions may be eligible for this study. Candidates will complete several written questionnaires about their jaw condition and will undergo a medical history, complete TMD evaluation, blood and urine tests, and imaging studies of the temporomandibular joint, such as X-rays and magnetic resonance imaging. Patients will rate the quality and intensity of their pain before beginning treatment. At certain periods during the study, they will also keep a pain diary, twice a day recording the intensity and magnitude of their pain.