Abstract A review of the literature on the impact of dental care on the incidence of dental caries in children and adults suggests that the effect is small. Dental services were relatively unimportant in explaining the recent decline in caries in 5- and 12-year-olds. An important contribution of the dental services to the decline in caries was a change in the diagnostic and treatment criteria. The role of dentistry in reducing dental caries may lie mainly in the non-personal health services. Knowledge of the life history and patterns of caries attack rates within populations and individuals could be used as a benchmark against which interventions can be assessed. Different teeth and tooth sites are affected differentially at different levels of dental caries. This truism may appear obvious but it is not used to evaluate the effectiveness and quality of dental treatment. A working rule is that “As caries prevalence falls, the least susceptible sites (proximal and smooth surfaces) reduce by the greatest proportion, while the most susceptible sites (occlusal) reduce by the smallest proportion.” There is a specific relationship between the mean DMFT and mean DMFS, and the percentage of caries-free subjects and the frequency distribution of subjects with different levels of caries. Furthermore, the best predictor of caries at older ages is DMFT at a younger age. Caries levels follow trend lines for each level of caries. As the mean DMFT declines so post-eruptive time increases for initiation of caries and the progression rates of caries through enamel decreases. This is true regardless of the presence of fluoride.