Abstract
Prevalence of caries was examined in 327 Japanese children, ranging in age from 0.6 to 16.5 with a mean age of 6.3, and expressed as DT%, DFT%, DS%, and DFS%, irrespective of the dentition. Mutans streptococci were also isolated from the saliva of the subjects and examined with respect to their serotypes, the ability of the sucrose dependent adherence, and extracellular glucosyltransferase activities. In twelve children, mutans streptococci were not found. The percentage of children who had S. mutans (serotype c/e/f), S. sobrinus (serotype d/g), or both of them were 75.9%,15.7%, and 8.4%, respectively. Salivary mutans streptococci were found to be significantly correlated to the prevalence of caries. Children with both S. mutans and S. sobrinus not only had higher salivary counts of mutans streptococci but also a higher caries prevalence than children with S. mutans or S. sobrinus alone. Also the correlation between caries prevalence and sucrose dependent adherence in children who had S. sobrinus was higher than that in children who had S. mutans. These results indicate that there may be some differences in the caries inducing mechanism between S. mutans and S. sobrinus in humans.
