Strains of mutans streptococci isolated in a population with extremely low caries prevalence are cariogenic in the hamster model

Strains of Streptococcus mutans and Streptococcus sobrinus freshly isolated from a population almost free of caries were examined in hamsters maintained on a high sucrose diet. The strains were readily implanted and persisted in high numbers during the experimental period. The test strains all induced caries, with caries scores equal to or higher than those of a reference strain of S. mutans. The results indicate that the strains have inherent cariogenic properties which are revealed under a frequent exposure to high concentrations of sucrose in the diet.