Effectivity of Irrigation Solution from Stevia rebaudiana Bertoni Leaf Extract on the Growth of Enterococcus faecalis Bacteries

Abstract

Disinfection of Enterococcus faecalis bacteria in dental root canal treatment using NaOCL 0.5-2.5% is still a challenge. There is still very little data on the effectvity of Stevia rebaudiana Bertoni leaf extract irrigation solution against the growth of Enterococcus faecalis. This study evaluated the effectiveness of Stevia rebaudiana Bertoni leaf extract irrigation solution against Enterococcus faecalis ATCC 29212  through MIC (Minimal Inhibitory Concentration) and MBC (Minimal Bactericide Concentration) values. A number of 100 µl of  E. faecalis suspension was inoculated into 96 microtitration wells, each containing 100 µl of 100%, 50%, 25%, 12.5%, 6.25%, 3.125%, 1.56% of Stevia leaf extract irrigation solutions, positive (NaOCL 2.5%) and negative (distilled water) control. Incubation was carried out for 24 hours at 37°C then optical density was measured with a microplate reader at 600 nm. Five µl of 10^-9 dilution of each group was dripped and spread onto nutrients agar plate. The number of Enterococcus faecalis colonies was counting manually. There was no significant difference in average colony count of Enterococcus faecalis between the 100% and 50% Stevia leaf extract irrigation solution groups and the positive control (p>0.05). However, the 25%, 12.5%, 6.25%, 3.125%, and 1.56% Stevia leaf extract irrigation solution groups showed significant differences (p<0.05). Stevia leaf extract irrigation solution suppressed growth at MIC 6.25% by turbidimetry and MIC 1.56%  by total plate count method using nutrient agar and than killed Enterococcus faecalis at MBC 50%. The bactericidal ability of 100% and 50% Stevia leaf extract irrigation solution is equal to NaOCL 2.5%.