Aim: The present study was done to determine the activity of licorice root extract on Streptococcus mutans (S. mutans) in comparison to chlorhexidine and fluoride mouthwash.
Materials and methods: In the current study, the different concentrations of aqueous and ethanolic licorice root extract were subjected to microbiological assay and zone of inhibition was determined against S. mutans by agar ditch method. Minimum inhibitory concentration (MIC) of aqueous and ethanolic solution was obtained by using broth dilution method and agar dilution method. Chlorhexidine and fluoride mouthwash were kept as a positive control in the present study. One-way ANOVA along with Tukey post hoc test were used at 5% level of significance to analyze data.
Results: Mean zone of inhibition of chlorhexidine mouthwash, fluoride mouthwash, aqueous and ethanolic licorice root extracts against S. mutans at 24 hours were 23 mm, 14.2 mm, 15.8 mm and 22.4 mm, respectively. Minimum inhibitory concentration of aqueous and ethanolic licorice root extract on S. mutans was 20 mg/mL and 12.5 mg/mL, respectively by both broth dilution method and agar dilution method.
Conclusion: The antibacterial effect produced by ethanolic licorice root extract on S. mutans was comparable to chlorhexidine mouthwash while significantly higher in comparison with aqueous form and fluoride mouthwash.
Clinical significance: The interest in the plants with antibacterial and anti-inflammatory activity has increased now days to treat various dental diseases as consequences of current problems associated with the conventional agents. Licorice root is easily available, economically feasible and culturally acceptable and may possess minimal side effects as compared to conventional means of chemicotherapeutic agents used for reduction of S. mutans in oral cavity and hence can be recommended for prevention of dental caries.
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