Intersections Between Skin Color, Sex and Income in Oral Health Disparities: A Population-Based Assessment of Brazilian Adults

OBJECTIVE: To analyze intersectional inequalities in dental service utilization and functional dentition among Brazilian adults aged 18-49 years, considering sex, skin color, and income. METHODS: Cross-sectional analysis of 64,811 adults reporting dental service use and 64,513 reporting functional dentition. Age-adjusted prevalences were estimated using Poisson regression with robust variance for combined sex/skin color/income strata. Absolute differences were calculated relative to White men with income above one minimum wage. Interaction contrasts on the additive scale (RERI) assessed departures from additivity. RESULTS: Black/Brown men with low income had the lowest utilization (33.6% vs. 57.8%; -24.2% points [p.p.], p < 0.001), while White women with high income had the highest (+ 6.3 p.p., p < 0.001). For absence of functional dentition, White women with low income had the highest prevalence (19.1% vs. 8.9%; +10.2 p.p., p < 0.001), followed by Black/Brown women with low income (14.8%; +5.9 p.p., p < 0.001). Income was the strongest predictor: service use decreased (- 12.8 to - 24.2 p.p.) and tooth loss increased (+ 4.6 to + 10.2 p.p.) across low-income groups, regardless of sex or skin color. Both outcomes showed sub-additive interaction contrasts, with joint effects not exceeding the sum of individual contributions (RERI for dental service use: -3.27 [95% CI: -6.52 to - 0.02]; RERI for non-functional dentition: -2.45 [95% CI: -5.18 to 0.28]). CONCLUSION: Intersectional inequalities were concentrated in low-income groups, with distinct patterns for women. The high burden of tooth loss among low-income White women suggests that socioeconomic and gender-related vulnerabilities may override racial privilege, rather than reflecting simple cumulative disadvantage.