into spasm, producing TMD (Chan, TMJ/Myofacial, 2002). The National Institutes of Health (NIH) have defined TMD as "a collection of medical and dental conditions affecting the temporomandibular joint and/or the muscles of mastication (chewing) muscles), as well as related tissue components" (Chan, What is, 2002). According to the NIH, over 10 million Americans suffer from TMJ, and 90 percent of these are women. TMD is also known as temporomandibular joint disorder (TMJ; craniomandibular dysfunction (CMD); craniofacial dysfunction (CFD); musculoskeletal dysfunction (MSD); and myofacial pain.
Causes of TMD: The correct alignment of the jaw may be affected by a number of things: the lower jaw may be too close to the upper jaw, causing over closure; the lower jaw may be too far back in the joint; the lower jaw may be off to one side or the other because of irregular tooth cusps (Chan, TMJ/Myofacial, 2002). Other causes include missing or lost teeth, wearing of teeth, clenching and grinding of teeth, improper tongue position, chronic mouth breathing (often due to allergies), osteoarthritis, rheumatoid arthritis, or trauma to the area. In 1990, statistics published in the Journal of the American Dental Association indicated that between 44 percent and 99 percent of TMJ problems are caused by trauma such as a blow to the jaw with a fist or a more subtle blow as received in whiplash injuries in car accidents (Shankland, 2002). Air bag deployment can also cause TMD pain. If the mouth is open wide for an extended time, such as in dental treatments or during surgery, ligaments may be torn, leading to TMD. The wearing of orthodontic braces can, in some cases, cause TMD. Stress may cause abnormal muscle tension and lead to TMD. Poor posture can also cause pressure on the TMJ and cause malocclusion (Chan, TMJ/Myofacial, 2002).
Dr. Clayton. A. Chan (Extraction, 2002) believes that the standard practice of extracting four bicuspi...