In-vitro adherence of oral streptococci in the presence of sucrose and its relationship to cariogenicity in the rat.

Streptococcus sanguis I gave a significantly greater percentage coverage (cell-pellicle attachment) of saliva-coated glass in the presence of sucrose than did Strep. sanguis II (p less than 0.025), and both these gave greater percentage coverages than the other species tested, between which no significant differences were noted. There was a large number of significant differences in clump size (cell-cell attachment) between species-pairs. Among the mutans streptococci, there were significant differences in the percentage coverage between Streptococcus rattus/Streptococcus mutans (p less than 0.05) and Strep. rattus/Streptococcus sobrinus (p less than 0.01), and in clump size between all species-pairs with the exception of Streptococcus cricetus or Strep. sobrinus and Strep. mutans. The rank order of species in relation to fissure caries was mutans streptococci greater than Streptococcus salivarius greater than Streptococcus milleri greater than Strep. sanguis greater than Streptococcus faecalis greater than Streptococcus mitis greater than Streptococcus lactis. There was a significant correlation between percentage coverage in vitro and fissure caries in vivo for strains of Strep. sanguis (p less than 0.05) and pooled strains of Strep. mitis and Strep. sanguis (p less than 0.01). On comparing data for adherence in the presence or the absence of sucrose, the sugar had no effect on the percentage coverage of the seven species tested, but significantly increased the clump size of the mutans streptococci (p less than 0.01) and Strep. sanguis (p less than 0.05).