Signs, symptoms, parafunctions and associated factors of parent-reported sleep bruxism in children: a case-control study.

Bruxism is the non-functional clenching or grinding of the teeth that may occur during sleep or less commonly in daytime. The aim of this study was to investigate the association between clinical signs and symptoms, parafunctions and associated factors of sleep bruxism in children. A population-based case-control study was carried out involving 120 children, 8 years of age, with sleep bruxism and 240 children without sleep bruxism. The sample was randomly selected from public and private schools in the city of Belo Horizonte, MG, Brazil. Groups were matched by gender and social class. The Social Vulnerability Index (SVI) drawn up by the city of Belo Horizonte was employed for social classification. Data collection instruments included clinical forms and pre-tested questionnaires. The diagnosis of sleep bruxism was supported by the American Association of Sleep Medicine (AASM) criteria. The McNemar test, binary and multivariate logistic regression models were used for statistical analysis. The risk factors associated with sleep bruxism included: primary canine wear (OR=2.3 IC 95% 1.2-4.3), biting of objects like pencils or pens (OR=2.0 IC 95% 1.2-3.3) and wake-time bruxism (tooth clenching) (OR=2.3 IC 95% 1.2-4.3). Children that present the parafunctions of object biting and wake-time bruxism were more susceptible to sleep bruxism.