Prevalence of probable sleep bruxism and associated factors in Brazilian schoolchildren.

Aim: To determine the prevalence of probable sleep bruxism (PSB) and associated factors among schoolchildren.

Design: This cross-sectional study was carried out with a representative sample of 440 schoolchildren. The children were submitted to a clinical oral examination for the evaluation of tooth wear and/or muscle discomfort. Parents/caregivers filled out a questionnaire with information related to characteristic sounds of sleep bruxism, sociodemographic factors, and the presence of harmful oral habits of children. The stress of the mothers was measured through the Lipp's Stress Symptoms Inventory for Adults (LSSI) instrument. The child's stress was measured through the Child Stress Scale (CSS). Data analysis included descriptive analysis and hierarchical Poisson regression (95% CI, P < 0.05).

Results: The prevalence of PSB was 40.0% (n = 176). The final Poisson regression model showed that PSB was significantly more prevalent in children with a history of nail biting (PR: 1.50; 95% CI: 1.19-1.90; P = 0.001) and biting objects (PR: 1.30; 95% CI: 1.03-1.63; P = 0.025) and less prevalent among girls (PR: 0.78; 95% CI: 0.63-0.98; P = 0.033).

Conclusions: The prevalence of PSB in schoolchildren was high. Schoolchildren with a history of nail biting and biting objects had a higher prevalence of PSB.