Ultrastructure of the condylar articular surface in severe mandibular pain-dysfunction syndrome.

Specimens from articular surfaces of normal human mandibular condyles are compared with very small biopsies from articular surfaces of condyles taken at conservative operations in severe pain-dysfunction syndrome (P.D.S.). Immediate fixation was followed by examination using transmission electron-micrography. Normal surfaces exhibit a nearly structureless layer about 2 micron thick, which corresponds with the lamina splendens described in other diarthrodial joints. This layer surmounts a dense main structure of wavy interlacing bundles of collagen interspersed with fibrocytes. Occasional straight elastic fibres were found. Surfaces of all condyles from P.D.S. patients showed loss of lamina splendens, alteration of collagen fibre size, and tendency to dissociation of both collagen and its surrounding ground substance. Depper levels showed aggregations of bizarre structures which the author terms "vermiform bodies", and which appear to be collections of abnormal amounts and types of elastic tissue. It is suggested that the appearances are those of stress elastosis. Such profound ultrastructural changes may affect the joint sliding properties, and also its mechanical integrity under stress. Examination at this degree of magnification suggests a direct relationship between long-standing pain-dysfunction syndrome and the onset of degenerative disease.