This study will examine the effectiveness of injected hylan (Synvisc) for treating pain associated with osteoarthritis of the temporomandibular joint (jaw joint) and improving function of the joint. Hylan is a synthetic product very similar to a component of normal healthy joint fluid (synovial fluid), which is present in much lower quantities and is abnormal in osteoarthritis. Hylan injections have been beneficial in treating osteoarthritis of the knee.