A wide literature shows a strong social gradient in tooth loss according to income, education and occupation, in both developed and developing countries. It has been shown associations between tooth loss and parental education and occupation, independently of adult conditions. To explore the role of early socioeconomic circumstances on tooth loss, we used a lifecourse model. We analysed the direct and indirect links between early socioeconomic conditions and severe adult tooth loss. We used the Costa Rican Longevity and Healthy Aging Study 1945-1955 Retirement Cohort, a nationally representative longitudinal survey of Costa Rican residents born between 1945 and 1955. We used imputed data on 2796 individuals. Principal component analyses were run to integrate measures approaching the material circumstances during childhood and adulthood. We additionally examined the role of adult health behaviours and education level as potential mediators in the multivariable regression. Early socioeconomic conditions were found strongly associated with severe tooth loss; 72.4% of the people who experienced the most deprived socioeconomic conditions during childhood (quartile 1) had severe tooth loss at the time of the interview; vs 43.3% in quartile 4 (most advantaged). This link diminished after adjustment for adult mediators. However, it remained a significant determinant of severe tooth loss in the final model. The lifecourse model allowed to highlight that early socioeconomic conditions could have long-term consequences on severe tooth loss in middle ages via both direct and indirect mechanisms. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.