Zeta potential and the adhesion of oral streptococci to polymethylmethacrylate

Adhesion of Candida albicans to the acrylic fitting surface of dentures can lead to the development of denture induced stomatitis and is suggested to be preceeded by the adhesion of indegeneous oral bacteria. Bacterial adhesion can be considered as a result of attractive van der Waals and repulsive electrostatic forces. In this paper we investigate the role of electrostatic interactions in the adhesion of oral streptococci to polymethylmethacrylate (PMMA), the most commonly employed denture-base material. Zeta potentials of the bacterial strains as well as of PMMA fillings were reduced by increasing the ionic strength in the buffer suspension, causing an elevated number of adhering S. mitis, S. sanguis and S. mutans. As streptococcal adhesion is suggested to be a prerequisite for the subsequent adhesion of Candida albicans, the use of more negatively charged denture-base materials can be recommended in order to prevent streptococcal adhesion and therewith adhesion of candidae, and the occurrence of denture-induced stomatitis.