AN EXAMINATION OF STRAINS OF THE BACTERIUM STREPTOCOCCUS-VESTIBULARIS FOR RELATIVE CARIOGENICITY IN GNOTOBIOTIC-RATS AND ADHESION INVITRO

The cariogenicity and adhesion of six strains of Streptococcus vestibularis were compared with those of strains of Strep. salivarius. All strains of Strep. vestibularis produced low levels of caries, confined to the fissures, whereas the two strains of Strep. salivarius produced high levels of caries, with one strain producing approximal as well as fissure caries. The values for adhesion to saliva-coated hydroxyapatite of Strep. vestibularis in the absence (median 4.74%) and the presence (median 4.67%) of sucrose were not statistically different, nor did they differ significantly from those of Strep. salivarius. Strains of Strep. vestibularis were able to adhere to buccal epithelial cells (median 1.19%) as well as could Strep. salivarius strain HB (1.65%). Neither sucrose nor saliva greatly aggregated the strains of either species. Strep. vestibularis did not adhere to hexadecane (median 18.5%) to the same extent as did Strep. salivarius strains (median 69%). There was a significant correlation between the adhesion in the presence and absence of sucrose (p < 0.01). Strep. vestibularis strains could not coaggregate with either actinomycetes or Veillonella spp. whereas Strep. salivarius strains were able to coaggregate with Veillonella spp.