Comparison of tooth surface-specific dental caries attack patterns in US schoolchildren from two national surveys

The 1979-1980 and the 1986-1987 National Institute of Dental Research (NIDR) surveys of school-aged children revealed that virtually all tooth surfaces experienced a decrease in caries prevalence during the inter-survey period. Overall, there was a 28% decrease in the proportion of tooth surfaces attacked by caries for the primary dentition between the two surveys. The decrease for primary incisors was numerically small (5 surfaces per thousand surfaces at risk) and not statistically significant, whereas decreases in the canines and primary molars were considerably larger (23 surfaces per thousand) and statistically significant. For the permanent dentition, the overall decrease in the proportion of surfaces attacked was 35% during the 1979-87 period. Differences between the two surveys in the proportions of surfaces with caries were largest for pit and fissure surfaces (56 surfaces per thousand), followed by those for posterior approximal surfaces (14 surfaces per thousand) and all other smooth surfaces (5 surfaces per thousand). Almost all of these differences were statistically significant, except for some surfaces which experienced very few caries.