Skin color affect the replacement of amalgam for composite in posterior restorations: a birth-cohort study

Abstract The aim of present study was to estimate the occurrence and associated factors for replacement of amalgam posterior restorations. A representative sample of all 5,914 births from the 1982 in Pelotas birth cohort study was prospectively investigated, and the posterior restorations were assessed at 24 (n = 720) and 31 years of age (n = 539). Individual-level variables, i.e., demographic characteristics, socio-economic factors, oral health conditions and use of dental services, were collected from different waves of the cohort. Tooth-level variables included dental group, estimated time in mouth of each amalgam restoration, and number of restored dental surfaces. Thus, 246 individuals presented 718 amalgam restorations at 24 years of age. After 7 seven years of follow-up, 18.9% of these restorations had been replaced with composite resins. Multilevel Poisson regression models showed that, compared to white individuals, blacks presented a lower risk of replacement of amalgam restorations for composite resins (IRR - 0.39 [0.16–0.95]). Individuals with high educational level at age 31 showed an increased likelihood of replacement of amalgam restorations. Therefore, skin color affects the replacement of amalgam for composite resin in posterior restorations.