TMD Pain Confounds the Association Between Bruxism and Anxiety

Objectives: To investigate possible predictor factors of sleep bruxism, and to test the hypothesis that temporomandibular disorders (TMD) pain could act as a confounder variable in the association between psychosocial factors and sleep bruxism.
Methods: The sample consisted of 1,094 adolescents, aged 12-14 years. Possible sleep bruxism was diagnosed by self-report. The presence of TMD pain was assessed clinically, using the Axis I of the Research Diagnostic Criteria for TMD. Single and multiple logistic regression models were used to identify associations between sleep bruxism on the one hand and gender, a family history of sleep bruxism, and psychosocial factors (viz., parents living together, anxiety, sadness, and difficulty with concentration/attention) on the other hand. A third variable model tested whether TMD pain confounds the association between psychosocial factors and sleep bruxism.
Results: The prevalence of sleep bruxism was 26.7%. Logistic regression analyses showed that sleep bruxism was associated with female gender (OR= 1.8; 95% CI= 1.34-2.37), positive sleep bruxism family history (OR= 2.5; 95% CI= 1.83-3.32), and anxiety (OR= 1.6; 95% CI= 1.08-2.22). The analyses revealed that TMD pain confounds the association between sleep bruxism and anxiety, because the significant association became non-significant after testing for a confounding effect (OR= 1.4; 95% CI= 1.00-2.05).
Conclusions: The present study is the first to investigate the confounding effect of TMD pain in the association between sleep bruxism and psychosocial factors. Future studies need to take this possible confounding effect into account.