In vitro susceptibility of streptococcus mutans 6715 to iodine and sodium fluoride, singly and in combination, at various pH values

Open Access
Publisher Website
Google Scholar
Abstract
The effect of pH on minimal bactericidal concentrations (MBCs) of sodium fluoride (NaF) and iodine (I2), singly and in combination, for Streptococcus mutans 6715 was investigated by using an in vitro checkerboard broth dilution assay. As pH was decreased, lower concentrations of NaF and I2 were required to exert a bactericidal effect. There was statistically significant linear correlation between pH and the MBCs of NaF (r = 0.95, P less than 0.001) and I2 (r ;.92, P less than 0.001). The MBCs of NaF were more affected by a change in pH than were the MBCs of I2; for every decrease of one pH unit in the range of pH 5 to 8, the MBC of NaF decreased fourfold, and the MBC of I2 decreased twofold. NaF and I2 in combination exhibited bactericidal effects on S. mutans which were additive at all pH values tested. These data indicated that the antibacterial properties of I2 and NaF, singly or in combination, can be enhanced by acidification.