Poor sleep quality and prevalence of probable sleep bruxism in primary and mixed dentitions: a cross-sectional study.

Purpose: To investigate the prevalence of probable sleep bruxism (SB) in the primary and mixed dentitions using non-instrumental approach and evaluate whether sleep quality is associate with probable SB in different age ranges.

Methods: School-based cross-sectional study with children aged 2-5 (primary dentition, n = 372) and 8-10 years old (mixed dentition, n = 563) enrolled in public schools at Florianopolis and their parents. The sleep characteristics, socioeconomic status, and presence of probable SB were assessed using questionnaires. Seven trained examiners (Kappa > 0.7) assessed tooth wear. Children were selected following a stratified sample (2-5); and a system of the proportionality, first the schools of the sanitary districts and after the classrooms (8-10). Unadjusted and adjusted Poisson regression was performed with probable SB as a dependent variable. Independent variables were as follows: family income, parent schooling, drooling, tooth wear, and sleep quality. The independent variables presenting p value ≤ 0.20 were included in the adjusted model.

Results: The prevalence of probable SB was 22.3% in primary and 32.7% in mixed dentition. Probable SB was significantly associated with poor sleep quality (p < 0.001) in mixed dentition (PR 1.80; 95% CI 1.34-2.44) adjusting for age and drooling. In the primary dentition, the adjusted regression did not show association between analyzed characteristic and probable SB. Sex, socioeconomic, head of the household educational status, drooling, and tooth wear were not associated with probable SB in both dentitions.

Conclusion: Prevalence of probable SB is higher in mixed than in primary dentition and poor sleep quality is associated with probable SB in children aged 8-10 years.