Association of temporomandibular disorder pain with awake and sleep bruxism in adults

OBJECTIVES: Parafunctional habits such as clenching or grinding (bruxism) during daytime and at night are considered to have a great impact on the etiopathogenesis of temporomandibular disorders (TMD). However, the size of the effect and how daytime activities interact with nocturnal activities is not yet clear. The aim of this study was to assess the association of TMD pain with both awake and sleep bruxism in adults.

MATERIALS AND METHODS: In this case-control study, data of a consecutive sample of 733 TMD patients (cases; mean age ± SD: 41.4 ± 16.3 years; 82% women) with at least one pain-related TMD diagnosis according to the German version of the Research Diagnostic Criteria for TMD (RDC/TMD) and of a community-based probability sample of 890 subjects (controls; mean age ± SD: 40.4 ± 11.8 years; 57% female) without TMD were evaluated. Clenching or grinding while awake and/or asleep was assessed with self-reports. Association of TMD pain with awake and sleep bruxism was analyzed using multiple logistic regression analyses and controlled for potential confounders. Odds ratios (OR) with corresponding 95% confidence intervals (CI) were calculated.

RESULTS: While 11.2% of the controls reported clenching or grinding while awake, this proportion was significantly higher in TMD patients (33.9%; p < 0.001). Nocturnal clenching or grinding was reported by 23.5% of the controls and 49.4% of the TMD patients (p < 0.001). Risk for TMD pain did not differ substantially for the separate reports of awake (OR 1.7; CI 1.0-2.7) or sleep bruxism (OR 1.8; CI 1.4-2.4). However, risk for TMD pain substantially increased in cases of simultaneous presence of awake and sleep bruxism (OR 7.7; CI 5.4-11.1).

CONCLUSION: When occurring separately, awake and sleep bruxism are significant risk factors for TMD pain. In case of simultaneous presence, the risk for TMD pain is even higher.