Maternal schooling and race/skin color jointly shape severe and untreated dental caries among 5-year-old Brazilian children

To assess whether maternal schooling modifies the association between race/skin color and severe untreated dental caries among 5-year-old Brazilian children and whether the pattern extends to untreated dental caries. Cross-sectional analysis of the nationally representative SB Brasil 2023 survey. Children aged 5 years with complete information on race/skin color, maternal schooling, sex and pufa status (n = 6462). Clinical consequences of untreated dental caries (pufa ≥ 1) were the primary outcome; untreated dental caries was examined in a sensitivity analysis. Race/skin color was categorized as white or non-white and maternal schooling as low or high. Survey-weighted logistic regression adjusted for child sex, and RERI assessed additive interaction. The prevalence of pufa ≥ 1 was highest among non-white children with low maternal schooling and lowest among white children with high maternal schooling. Compared with non-white children with low maternal schooling, white children with high maternal schooling had lower odds of pufa ≥ 1 (OR = 0.30; 95% CI: 0.24–0.38). The RERI estimate suggested positive additive interaction for pufa ≥ 1, although the confidence interval included the null value (RERI = 0.13; 95% CI: −0.05 to 0.31). Untreated dental caries followed the same pattern (RERI = 0.15; 95% CI: 0.02–0.28). Race/skin color and maternal schooling were jointly associated with severe untreated dental caries among Brazilian preschool children. This pattern was observed for untreated dental caries, indicating broader unmet treatment needs among socially disadvantaged children.