Unhealthy Dietary Habits and Sedentary Behavior Drive Untreated Dental Caries among Adolescents: A Population-Based Study

Untreated dental caries remains a significant public health challenge, particularly among adolescents, where it can compromise well-being and quality of life. This population-based study investigates the factors associated with untreated dental caries in 12-year-olds across the five most populous cities (each with >80,000 inhabitants) in the state of Mato Grosso do Sul, Brazil. Using WHO criteria, clinical oral examinations and self-reported behavioral data were collected. Guided by a social determinants of health framework, we conducted univariable and multilevel logistic regression analyses to explore associations between untreated dental caries and individual, behavioral, and contextual factors. The prevalence of untreated dental caries was 25.3% (95% CI: 18.8–33.1). Protective factors included household income above the poverty line [OR = 0.55 (95% CI: 0.33–0.91)], exposure to fluoridated water [OR = 0.58 (95% CI: 0.28–0.99)], and brushing more than twice daily [OR = 0.54 (95% CI: 0.32–0.91)]. In contrast, adolescents reporting frequent consumption of unhealthy foods [OR = 5.00 (95% CI: 2.21–11.62)] and sedentary behavior [OR = 1.56 (95% CI: 1.00–2.52)] were more likely to present untreated caries. Our findings highlight the interplay between socioeconomic context, lifestyle behaviors, and access to preventive measures. To reduce the burden of untreated dental caries in adolescence, oral health interventions must adopt a transdisciplinary approach that addresses broader social and behavioral determinants—promoting healthier diets, reducing sedentary time, and ensuring access to fluoridated water.