Objectives: To compare the antimicrobial effects of Nigella sativa (N.Sativa-0.3%) and sodium hypochlorite (NaOCl-5%) root canal irrigation solutions against Enterococcus faecalis (E.Faecalis), utilizing ultrasonic, and laser activation methods in extracted teeth.
Material and methods: Seventy extracted human single-rooted teeth with single canals were instrumented, sterilized, and inoculated with Enterococcus faecalis. After 21 days of incubation, the samples were randomly divided into seven groups (n=10) including a negative control group. The tested irrigations Nigella sativa -0.3% and NaOCl-5% were subdivided according to the activation protocol: no activation, passive ultrasonic irrigation Irrisafe ultrasonic tips and laser-assisted irrigation (Waterlase: Er,Cr,YSGG).
Shaved dentin chips were obtained and collected by H-files and paper points, for bacterial culture. The antibacterial activity was assessed using bacterial colony-forming units per milliliter (CFUs/ml). Mann Whitney U test and Kruskal-Wallis H test were used (P<0.05).
Results: Significant reduction was obtained with all tested groups except for the non-activated Nigella sativa -0.3%. NaOCl-5% demonstrated the significant greatest antimicrobial efficacy with each irrigation protocol. Non-significant difference existed when comparing the anti-microbial efficacy of non-activated NaOCl-5% to the laser activated Nigella sativa -0.3%.
Conclusions: The group of non-activated Nigella sativa was the unique group that failed to show a significant anti-microbial efficacy against Enterococcus faecalis. Sodium hypochlorite exhibits the highest statistically significant efficacy in the eradication of Enterococcus faecalis bacterial biofilm, disregarding the activation method used.
The laser potentiates the anti-microbial effect of Nigella sativa extract to the extent of reaching the efficacy of non-activated high concentration of sodium hypochlorite solution.