Evaluation of Anti-bacterial Effect of Ammonium Hexafluorosilicate on Streptococcus mutans and Lactobacilli

Abstract Background: Although dental caries is a common problem in the world, fluoride application is one of the most effective ways to prevent tooth decay. Ammonium hexafluorosilicate (AHF) has recently been studied as a promising anti-caries and hypo-sensitive agent. Objectives: This study was conducted to evaluate the antibacterial activity of AHF against S treptococcus mutans ( S. mutans ) and Lactobacilli and the cytotoxicity of AHF. Materials and Methods: Diffusion well test was used to test the sensitivity of the bacteria. The anti-bacterial effect was evaluated by measuring the inhibition zone of the study (AHF), control +ve (chlorhexidine 0.2%, sodium fluoride 2%) and control −ve (deionized water) groups against the growth of S. mutans and Lactobacilli . For AHF, different concentrations were used (0.1, 0.32, 0.75, 1.25, 2.5, 5, 10, 15, 20) mg/mL. A serial dilution technique was performed to measure the minimum inhibitory concentration (MIC). The tested solutions were then cultured to the specified minimum bactericidal concentration (MBC). The Mosmann’s tetrazolium toxicity assay was used to test the cytotoxic effect of AHF on the normal cell line. Data were analyzed using Shapiro-Wilk, one-way ANOVA, and Tukey’s multiple comparison test. Results: The AHF had a statistically significant antibacterial effect against S . mutans and Lactobacilli and increased with increasing concentration. About 10 mg/mL of AHF MIC, 20 mg/mL of MBC, and 10,000 μg/mL of AHF were not toxic. Conclusion: AHF exhibited significant antibacterial activity by showing a clear zone against S. mutans and Lactobacilli. Thus, it can be considered as a promising anticariogenic material in the future.