Interference of Antimicrobial Activity of Combinations of Oral Antiseptics Against Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus acidophilus

The purpose of this study was to compare the effects of combinations of sodium fluoride and antiseptic compounds on the growth of Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus acidophilus.

The agar diffusion assay was used to determine bacterial growth inhibition.

Of the combinations tested, 0.1 percent sodium fluoride and five percent povidone iodine produced synergistic antibacterial effects against S. mutans and S. sanguinis. The combination of 10 percent povidone iodine and 0.5 percent sodium hypochlorite produced additive antibacterial effects against L. acidophilus. Interference was seen in some combinations such as 0.01 percent chlorhexidine and 0.25 percent sodium lauryl sulphate, 0.5 percent sodium hypochlorite and 10 percent povidone iodine, and 0.01 percent cetyl pyridium chloride and 0.1 percent sodium fluoride. However, 0.1 percent sodium fluoride combined with 0.01 percent chlorhexidine did not interfere with the antibacterial effects of chlorhexidine against S. mutans or S. sanguinis.

Combinations of common antiseptics and fluoride compounds can produce interference, synergistic, or additive effects. The combination of 0.1 percent sodium fluoride and five percent povidone iodine had the greatest potential for suppression of S. mutans.