Tissue Reactions of the Temporomandibular Joint Following Retrusive Guidance of the Mandible

Tissue reactions in monkey temporomandibular joints (TMJs) were studied following retrusive guidance of the mandible. Eleven adult Macaca fascicularis monkeys were used (four experimental animals and seven controls). Interferences between intercuspal position and retruded position were eliminated in the experimental animals. Bilateral interferences were then introduced to guide the mandible into retruded position during mouth closure. The experimental period lasted for five weeks.After radiographic examination, the joints were histotechnically processed, and sagittal sections were taken throughout the joints for light microscopy. In contrast to the untreated animals, the experimental monkeys demonstrated pathological changes in the posterior band of the disk and posterior disk attachment. The flattening of the posterior band of the disk that occurs with retrusive guidance may predispose subjects to anterior disk displacement.