RESUMEN
Objective: To compare and evaluate antimicrobial efficacy of chlorhexidine gluconate and fennel seeds against Streptococcus mutans. Material and Methods: Three agar petri dishes for Streptococcus mutans were prepared. The methanolic extract of fennel seed and 0.2% chlorhexidine were inoculated on the each petri dish and incubated at 37ºC for 24 hours. Zone of growth inhibition for each extract was measured in millimeters using antibiotic inhibiting zone measuring scale. Data was analyzed using SPSS statistical software. The comparison of inhibition zone against S. mutans using CHX and fennel seed extract was done using Mann-Whitney and Wilcoxon tests. All statistical analyses were set at a significance level of p<0.05. Results: The mean of zone of inhibition of S. mutans after inoculation with 0.2% chlorhexidine and fennel seed extract are 21.44 ±1.46, 15.34 ±0.74 respectively. There was statistically significant difference in the mean of inhibition zone between 0.2% chlorhexidine and fennel seed against S. mutans (p=0.047). Conclusion: Chlorhexidine and fennel seed are effective in inhibiting the growth of cariogenic bacteria. Therefore, both herbal and chemical agents can be effectively used to reduce pathogenic oral microflora.