Effectiveness of stannous fluoride and calcium hydroxide against Enterococcus faecalis

The objective of this study was to evaluate the antimicrobial activity of stannous fluoride, calcium hydroxide, or the two in combination against Enterococcus faecalis. Fifteen Mueller-Hinton agar plates were used to conduct a disc diffusion susceptibility test. The plates were inoculated with E. faecalis. The groups tested were: (a) stannous fluoride (Stanimax); (b) calcium hydroxide; and (c) a combination of stannous fluoride and calcium hydroxide. Three filter paper discs, each soaked with one of the groups, were placed along with an antibiotic control (ampicillin) on each agar plate. The plates were then incubated at 37degreesC. The zones of inhibition were measured at 24 and 48 h. One-way ANOVA revealed a statistically significant difference (p < 0.05) between the three groups. Stannous fluoride displayed the widest zone (1.7 mm), followed by the combination of stannous fluoride and calcium hydroxide (1.1 mm), whereas calcium hydroxide by itself displayed a minimal zone of inhibition (0.05 mm).