Stress is simultaneously related to sleep and temporomandibular disorders.

Purpose: This study aimed to clarify the relationship between the oral environment and psychological factors as predictor variables of sleep quality, in addition to inferring the relevant mechanisms of sleep and temporomandibular disorders (TMDs) by analyzing the relationship between TMDs and stress.

Methods: This cross-sectional study analyzed data from 1,032 participants, comprising 420 men and 612 women, from the 2017 Iwaki Health Promotion Project using multiple regression analysis. The primary endpoints were the scores of each item in the Pittsburgh Sleep Quality Index (PSQI) and its sum. Predictor variables included the number of teeth; TMDs; stress, assessed using the World Health Organization-5 (WHO-5); sleep bruxism; and oral health-related quality of life, assessed using the oral health impact profile-14 (OHIP14). The confounding factors included age, body mass index, and alcohol intake.

Results: Multiple regression analysis revealed that TMDs (β value = 0.293, p = 0.034) and stress (β value = 1.3, p < 0.001) were significantly correlated with the PSQI total score. In addition, TMDs were significantly correlated with stress (β value = 0.076, p = 0.007).

Conclusion: The significant relationship between sleep and TMDs suggests that mental stress contributes to the development sleep disorders and consequently is associated with the development of TMD symptoms.