Psychological stress induces alterations in temporomandibular joint ultrastructure in a rat model of temporomandibular disorder

Objective. The objective of this study was to investigate the effects of psychological stress on temporomandibular disorder (TMD). Study design. A communication box was used to induce psychological stress (PS) in rats. Then, the ultrastructure of temporomandibular was observed using scanning electron microscopy. Interleukin-1 (IL-1) and IL-6 were measured with reverse transcription polymerase chain reaction. Results. The PS group showed evidence of ultrastructural changes in the condyle and articular disk after stimulation, i.e., incomplete gelatinlike material was observed on the condyle after 1 week of PS, wider waves on the articular disk and exposed condylar collagen were observed after 3 weeks of PS, and cracks were apparent on the surface of the condyle. The expression of IL-1 and IL-6 in the condyle cartilage significantly increased after exposure to psychological stress. Conclusions. These results indicate that psychological stress induces ultrastructure alterations in the temporomandibular joint and plays an important role in TMD. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011; 112: e106-e112)