This follow-up of the oral health of children and young adults in Espoo, Finland, has been carried out using annual check-ups done by dentists at the Espoo Health Center. There was about 80% participation in municipal dental care by 3- to 18-yr-olds. Each age group included 1700-2300 individuals. The DMFT-index for 12-yr-olds was 6.9 initially and only 2.2 at the end of the 12-yr follow-up. The reduced DMFT and increased number of clinically caries free children is probably the cumulative effect of various preventive measures adopted during the follow-up period. The proportional influence of each procedure is unknown.