Objective: To assess whether socioeconomic factors are associated with the progression of caries, independently of a previous history of caries.
Subjects and methods: In 1995, as part of a longitudinal study of preventive measures, 3373 Swedish 12-year-olds were examined for caries and answered a questionnaire regarding socioeconomic level (SEL), ethnicity and residential area. The examination was repeated in 1997 when 3109 of the teenagers participated. Baseline caries and increments in the incidence of caries were computed. The influence of structural variables on baseline caries as well as a 2-year increment were analysed by means of Poisson regression.
Results: The risk of having caries as 12-year-olds was greater in workers' and immigrants' children, as well as in urban teenagers. The risk of developing new caries was most influenced by an earlier experience of caries. The social gradient was, however, still visible when a previous experience of caries was accounted for. The pattern found in the cross-sectional data from 1995, with more caries in children from workers' families, therefore prevailed in the increment data.
Conclusion: Irrespective of earlier caries status there is a social gradient in caries progression. It therefore seems that the preventive methods do not function to the equal benefit of all children.