In Vitro Antimicrobial Activities against Streptococcus Mutans: A Comparative Study of Green Versus Black Tea Extracts and 0.2% Chlorhexidine and Fluoride

Abstract

Introduction: The aim of the present study was to evaluate and compare the antibacterial effects of black and green tea extracts with those of 0.2% sodium fluoride and chlorhexidine (CHX) mouth rinse on SM in- vitro. Methods: In this in-vitro study the effects of fluoride and CHX mouth rinse, black and green tea extracts on SM PTCC 1683 were evaluated and compared using the minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) technique and disk diffusion method by measuring the diameters of inhibition zones. Descriptive statistics were retrieved and data was analyzed using Mann-Whitney and Kruskal-Wallis analysis. Statistical significance level was established at p < 0.05. Results: MIC and MBC of black and green tea extracts were similar (62.5 mg/mL), with 0.125 and 2 mg/mL for CHX and fluoride, respectively. The inhibition zones for pure green and black tea extracts and CHX were 16.05, 11.77 and 9.91 mm, respectively. The green tea had the larger inhibition zone than CHX and fluoride. (P value <0.01) There was no significant difference between green and black tea. (P value =0.23) Conclusion: The green and black tea had similar antibacterial effect on 62.5 to 1000 mg/ml concentrations. The anti SM activity of CHX and fluoride appears on a lower concentration than green and black tea extracts. However, the inhibitory effect of green tea at higher concentration was significantly more than CHX and fluoride. In general, the antibacterial effects of green tea, black tea and CHX were significantly higher than fluoride.