We assessed whether 3 models of life course socioeconomic status (critical period, accumulation of risk, and social mobility) predicted unsound teeth in adulthood among a Brazilian cohort. Life course data were collected on the 5914 live-born infants in the 1982 Pelotas Birth Cohort study. Participants' oral health was assessed at 15 (n = 888) and 24 (n = 720) years of age. We assessed family income trajectories and number of episodes of poverty in the life course through Poisson regressions, yielding unadjusted and adjusted prevalence ratios for number of unsound teeth at age 24 years. The adjusted prevalence ratio for participants born into poverty was 30% higher than for those who were not. Participants who were always poor had the highest prevalence of unsound teeth; those who were downwardly or upwardly mobile also had more unsound teeth than did other participants, after adjustment for confounders. More episodes of poverty were associated with greater prevalence of unsound teeth in adulthood. Poverty at birth and during the life course was correlated with the number of unsound teeth at 24 years of age.