Light microscopic and ultrastructural study of thinned discal areas in patients with temporomandibular joint internal...

It is generally believed that pathological destruction of the articular tissue occurs whenever articular remodeling does not maintain a balance between its structure and function. Remodeling is a natural cellular response contingent on the capability and availability of viable cells. Remodeling maintains the anatomic integrity of individual cells. Remodeling maintains the anatomic integrity of individual joint components that sustain the wear and tear occurring normally in the joint while accomplishing work. If the mechanical forces are within the physiological tolerance of the articular structures, cellular repair will keep up with destruction to protect the joint from deformation. It is hypothesized that the TMJ disc lacks the reserve remodeling capacity that characterizes the condyle and articular eminence. The lack of blood supply to the disc proper renders it dependent on nutrient diffusion from an intact synovial film. Many factors may change both the composition and the continuity of this nutritional source. Therefore, the synovial fluid may be the solitary source of nutrition for cellular healing and remodeling of the avascular part of the joint. Carlsson et al. felt that longstanding increased compressive forces on the disc may lead to cell necrosis and matrix degradation culminating in thinning of the disc and subsequent perforation.