Caries status and microbial conditions in children in 1973 and 1984.

In 1973 all 9-12-yr-old children in a county in Sweden were examined with regard to caries prevalence, salivary Streptococcus mutans and lactobacilli. Eleven years later the same parameters were analyzed in 250 randomly selected children of the same age and from the same county. Both the number of cariogenic microorganisms and the caries prevalence were significantly lower in 1984 than in 1973 (P less than 0.001). The lower number of S. mutans and lactobacilli could be due to several factors and is probably one of the reasons for the low caries prevalence in the children in the present study.