Objectives: To evaluate in vitro effect of zeta potential and hydrophobicity of three oral pioneer strains on their initial adherence to enamel.
Materials and methods: Hydrophobic properties of oral pioneer strains (S. sanguinis, S. oralis and S. mitis) and dental enamels were assessed by MATS (Microbial affinity to solvent) test and contact angle measurements respectively. The zeta potentials of the cells surfaces and enamel powders were measured using Zeta Potential Analyzer. SEM was used to enumerate oral bacteria adherent on enamel.
Results: Enamel surfaces were hydrophobic and negatively charged. S. sanguinis, S. oralis and S. mitis significantly differed in hydrophobic properties with percentages of affinity to hexadecane being 92.5, 81.3 and 46.2% (P < 0.01), and with zeta potentials being -14.59, -19.57 and -13.51mv respectively (P < 0.01). The adherent number of S. sanguinis was higher (14361/mm2) than that of S. oralis (5162/mm2) and S. mitis (3225/mm2) (P < 0.01). Bacteria with more hydrophobic and less negative zeta potential demonstrated greater adherence to enamel.
Conclusion: Both hydrophobicity and zeta potential of cell surfaces may have significant influence on bacterial adhesion to enamel.