Dental caries and alveolar bone loss in gnotobiotic rats infected with capsule forming streptococci of human origin

Abstract

Strains of streptococci have been isolated from each of three human carious lesions which proved cariogenic when tested in pure culture in gnotobiotic rats. The presence of two of these strains also resulted in extensive localized loss of alveolar bone. A streptococcus strain isolated from one of the human carious lesions studied was unable to induce caries in gnotobiotic rats. The biochemical and serological characteristics of these organisms indicate that the human cariogenic strains are similar to rodent cariogenic streptococci. Seven rodent and human cariogenic streptococci have been found to synthesize large quantities of extracellular non-dialysable capsule like carbohydrate from sucrose, while three strains of non-cariogenic streptococci formed lesser amounts, suggesting that capsule formation may be important in the caries process.