Osteoarthritis of the temporomandibular joint organ and its relationship to disc displacement.

To overcome disagreements with regard to the relationship between disc displacement and osteoarthritis of the temporomandibular joint (TMJ), the evidence for suggested disease mechanisms and clinical course of these disorders is reviewed. The TMJ behaves as a complex organ in which biochemical and biomechanical processes regulate the physiology of cartilage, bone, synovium, ligaments, and synovial fluid. In this concept, TMJ osteoarthritis is an organ failure involving all its structures. The development of as well as recovery from disease appears to be intimately related to exceeding and supporting the adaptive capacity of the tissues that make up the joint organ. Loss of fibrocartilage and inflammation appear to be major pathobiologic processes, while serious doubts exist about the significance of disc position in joint pathology.