Abstract
BACKGROUND: This study compared the antibacterial effects of 940 nm diode laser and sodium hypochlorite and chlorhexidine irrigations on Enterococcus faecalis in human permanent single-rooted teeth. MATERIALS AND METHODS: In this in vitro study, 65 extracted human single-rooted teeth were prepared using the crown-down method using rotary files. The root canals were irrigated with 5.25% sodium hypochlorite, 17% ethylenediaminetetraacetic acid, and normal saline solution. After placing the roots in microtubules, they were transferred into an autoclave. The teeth were randomly divided into four groups (n = 15): laser, sodium hypochlorite, chlorhexidine, and saline. Three teeth were assigned to the positive control group and two to the negative control group. The root canals were sampled, and the colony counts were determined 24 h later. Then, antibacterial agents were applied to the canals, and immediately after, the root canals were sampled, and the colony counts were determined 24 h later. The data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests using the SPSS software version 26. The significance level was defined at P < 0.05. RESULTS: The results showed that sodium hypochlorite, chlorhexidine, laser, and normal saline significantly reduced bacterial colony counts, confirming their antimicrobial effects (P < 0.001). Sodium hypochlorite and chlorhexidine showed the highest antimicrobial effects, with no significant differences between the sodium hypochlorite and chlorhexidine groups (P = 0.512); however, there were significant differences between the other groups (P < 0.001). CONCLUSION: According to the results, 940 nm diode laser beams significantly reduced E. faecalis counts and could be used as a new, effective, and complementary treatment in disinfecting the root canal.