Abstract
The relationship between serum complement-fixing antibodies against streptococcal cell walls and the incidence of caries was studied in 116 subjects. The series was divided into an ‘active caries’ (AC) group and a ‘caries-free and treated caries’ (CFTC) group, and the antibody titres were correlated with the index of decayed, missing and filled (DMF) teeth. In the CFTC group, a significant negative correlation coefficient was found with three strains of Streptococcus mutans which have been shown to be cariogenic in animals. A positive correlation was found with these streptococci in the AC group. A similar relationship was not apparent between the DMF index and the antibody titre to two non-cariogenic streptococci with either the CFTC or AC group.