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.