A cross-sectional survey was carried out. This involved 652 out of a total of 764 (85%) 13-year-old adolescents enrolled in private and public schools located in urban areas in Cianorte, Brazil. They were interviewed and examined for traumatic dental injuries by one trained examiner (B.N.) using validated criteria. Sociodemographic data included sex, family structure (nuclear families, single parents and step-parents) and socio-economic indicators. Anthropometric measures included height and weight. The body mass index (BMI) was calculated (mean=20.1; SD=3.7). Those who had BMI scores equal or above the 85% percentile were considered overweight (BMI >23). The prevalence of traumatic injuries to the permanent incisors was 20.4%. The most common reported cause of injuries to the permanent incisors was falls (24.1%) followed by collisions with people or inanimate objects (15%), traffic accidents (10.5%), misuse of the teeth (6%), sports (2.3%) and violence (1.5%). Unknown causes accounted for 40.6%. Children from non-nuclear families, overweight children and boys were 2.18, 1.93 and 2.19 times respectively more likely to have dental injuries than children from nuclear families, non-overweight children and girls (P<0.01) after adjusting for family structure, BMI, sex, family income and level of education of the parents. The relationship between dental injuries and socioeconomic indicators was not statistically significant. In conclusion, being from a non-nuclear family, overweight and a boy increased the risk of having traumatic dental injury, but the relationship with socio-economic indicators was not statistically significant.