The effects of basic and acidic synthetic polypeptides on the adherence of the oral bacteria, Streptococcus mutans and Streptococcus sanguis, to hydroxyapatite.

Two basic and two acidic synthetic polypeptides that bind strongly to hydroxyapatite at neutral pH were tested to determine their influence on adsorption of two Streptococcus mutans and two Streptococcus sanguis strains to hydroxyapatite. The adsorption of the strains was significantly enhanced or reduced by the basic and acidic agents, respectively. Study of acidic polypeptides provided evidence of competition between the polypeptides and the bacterial cells for hydroxyapatite adsorption sites.