Trends in caries prevalence in North American children.

Data for caries in the permanent and primary dentitions of children in Mexico, the United States, and Canada are reviewed from the years around 1982 to the present time. Sources are national, state, and provincial surveys, together with a number of smaller, local surveys. Data from minority populations are also reviewed. Conclusions are that caries prevalence and severity in the permanent dentition are continuing to decline in the general populations of Canada and the United States, but that caries experience in the primary dentition may have stabilised since around 1986-87. There is nothing in the limited data available from Mexico to suggest a decline in that country, caries levels remaining high. There are considerable geographic variations in caries experience in the general populations of the United States and Canada; the highest prevalence and severity is found in Quebec. Caries is more prevalent and severe in the indigenous populations of Canada and the United States than in the general population, but there are indications of a decline in the permanent dentitions of those indigenous groups. Caries will probably decline further in the general populations of Canada and the United States before it reaches an irreducible minimum, but that point may not be far away because caries experience is already very low in many localities. It is anticipated that the recent introduction of salt fluoridation in Mexico will help to bring down the high caries levels in that country.