Relationship between self-reported sleep bruxism and pain in patients with temporomandibular disorders.

The aim of this study was to evaluate the association between self-reported sleep bruxism and the age, gender, clinical subtypes of temporomandibular disorders (TMD), pain intensity and grade of chronic pain in patients previously diagnosed with TMD. Thousand two-hundred and twenty patients of the Andalusian Health Service were examined using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) questionnaire. The inclusion and exclusion criteria were those included in the RDC/TMD criteria. The bruxism diagnosis was drawn from the question, 'Have you been told, or do you notice that you grind your teeth or clench your jaw while sleeping at night?' in the anamnestic portion of the questionnaire. A bivariate analysis was conducted, comparing the presence of perceived parafunctional activity with age (over age 60 and under age 60), gender, different subtypes of TMD, pain intensity, grade of chronic pain and presence of self-perceived locked joints. The overall prevalence of self-reported sleep bruxism (SB) was 54.51%. A statistically significant association was found between the presence of SB and patients under age 60, women, greater pain intensity, greater pain interference with activities of daily living, and the axis-I groups affected by both muscular and articular pathology. There is a statistically significant association between self-reported sleep bruxism and women under age 60 who have painful symptoms of TMD. There is also a positive association between this parafunctional habit and the presence of chronic pain. However, more studies that cover larger samples and differentiate between sleep bruxism and awake bruxism are needed.