The controversy concerning whether or not extraction of bicuspids for orthodontic purposes causes temporomandibular joint disorders (TMD) has been argued for over 20 years. It began in the late 1980s after litigation on behalf of TMD patients claiming that the cause of their problems was orthodontic extractions (McNamarra, 1997). The question is still being debated, although there seems little evidence that removal of teeth actually causes TMD. Orthodontists remove teeth in cases of overcrowding to allow normal occlusion of the upper and lower jaws and normal jaw and tooth development. This is still done in some cases, although orthodontists now rely more on repositioning of teeth through the use of braces and orthodontic appliances. Those opposed to bicuspid extraction argue tooth overcrowding in the upper jaw (maxilla) is due to a small upper arch, and removing teeth will only make it smaller, making proper occlusion even more difficult (Chan, 2002).
The temporomandibular joint connects the lower jaw, known as the mandible, to the temporal bone of the skull (Chan, TMJ/Myofacial 2002). The two bones are separated by a disc of articular cartilage, and the head of the mandibular bone fits into a concavity in the temporal bone called the genoid fossa. The joint also contains muscles, soft tissue and ligaments. Both temporomandibular joints (TMJ) (right and left) move together as the jaw is opened and closed. Normally the joint moves smoothly and quietly. The TMJ joints are the most complex joints in the body because they go through both rotational and sliding movements in an infinite variety of combinations with movements of the jaw. Their movements are unlike those of any other joint in the entire human body.
Temporomandibular Joint Disorder (TMD):
Definition: The mandible and the maxilla have a definite relationship to each other, and if this relationship is disturbed in any way, the muscles in the joint go ...