Inhibitory effect of stannous fluoride and other commonly used antimicrobial agents on oral bacteria

The purposes of this investigation were to evaluate and compare the antimicrobial effect of stannous fluoride (SnF2) gel and other commonly used oral antimicrobial agents/products. The antibacterial inhibitory effect of the various agents was evaluated by their effect against oral plaque bacteria including strains of Streptococcus sanguis, Streptococcus sobrinus, Actinomyces viscosus, Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius. A lawn of the specific bacteria to be tested was placed onto blood agar plates. Wells were then punched into the agar and each well was filled with 75 microliters of one of the antimicrobial products or control solutions. A positive control was a 0.12% chlorhexidine solution and a negative control was physiological saline. Agar plates were incubated in an anaerobic chamber at 37 degrees C for 5-7 days. Zones of inhibition in the lawn of bacteria were measured by a boley gauge. Each experiment was performed in duplicate and mean zones of bacterial inhibition were determined. Only 0.4% SnF2 and 0.12% chlorhexidine were consistently more effective in inhibiting oral bacteria when compared with other commercial mouth rinses/agents which had any one of a variety of antimicrobial agents as ingredients (alpha = 0.05). This in vitro study demonstrates that stannous fluoride gel is as effective as chlorhexidine in inhibiting the growth of bacteria often found in dental plaque.