Streptococcal adherence on various restorative materials.

The adherence of Streptococcus sanguis ATCC 10556, S. sanguis ATCC 10557, S. mutans Ingbritt, and S. mutans OMZ 176 to the surfaces of composite resins, amalgam alloys, and a Au-Ag-Pd alloy was measured. Adhesion was correlated with values for hydrophobicity and zeta-potential of the bacteria and the restorative materials. The hydrophobicity of the restoratives showed a positive correlation between the numbers of adherent S. sanguis cells, suggesting that hydrophobic interactions are important for the adherence of this bacterial species. In contrast, the numbers of adherent S. mutans cells showed a positive correlation with the zeta-potential of the restoratives, suggesting that electrostatic interactions are important in adherence of this bacterium.