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.