1996 Volume 59 Issue 2 Pages 179-192
We investigated factors affecting the zeta potential of mutans streptococci, and how changes in zeta potential influence surface potential energy. Zeta potential of nine species of mutans streptococci were measured in phosphate buffer solutions of various pH and ion strengths. The strength of adsorption of bacteria to hydroxyapatite was measured as the maximum surface potential energy (Vmax), while the broth dilution method was used to measure minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).
Zeta potential of the bacteria was related to serotype and growth speed and was very dependent on pH and ion strength. It had a greater negative value with PO43- and a smaller negative value with F-, Al3+, Sn4+ and chlorhexidine. Results for MIC and MBC indicated that NaF and chlorhexidine produced changes in zeta potential for different reasons than did other chemicals. Although the Vmax between hydroxyapatite and bacteria with high zeta potential was influenced by pH, ion strength, and the presence of F-, Al3+, Sn4+ and chlorhexidine, the Vmax between hydroxyapatite and bacteria with lower zeta potential was influenced only by ion strength.
We found that the zeta potential of mutans streptococci was affected by pH, ion strength and the presence of multivalent cations. This suggests that adhesion of bacteria to hydroxyapatite can be inhibited by increasing pH, decreasing ion concentration, and not incorporating multivalent cations in the solution. Shika lgaku (J Osaka Odontol Soc) 1996 Jun; 59{2): 179-192.
