Evaluation the effect of different laser powers on the Enterococcus faecalis infected root canals: An in vivo study

Abstract

Aim: To assess in vivo the immediate and delayed disinfecting efficacy of erbium,chromium:yttrium scandium gallium garnet (Er,Cr:YSGG) laser against Enterococcus faecalis at the output powers 1, 1.5, and 2 W with a 20s period of time. Materials and Methods: Study criteria include 45 single-rooted teeth. Patients were randomly divided into three groups (gps) (n = 15/gp) according to the output powers selected in this study. After access opening, first microbiological samples (S1) were collected immediately before Er,Cr:YSGG laser treatment. Second microbiological samples (S2) were taken immediately after instrumentation and laser disinfection at the output powers 1, 1.5, and 2 W with 20s period of exposure time. Third samples (S3) were collected after 1 week of irradiation. The obtained samples were transferred to an agar plate and incubated for 48h at 37°C. The colonies of E. faecalis formed were then counted. The collected data were analyzed using one-way analysis of variance (ANOVA) analysis and Duncan multiple range tests at level P ≤0.05. Results: The result showed no significant difference between number of bacteria before laser treatment and after 1 week of laser application at the output power 1 W. However, significant difference was detected immediately after laser application. At 2 W a significant difference was observed between number of bacteria before laser treatment and after treatment with no difference between number of bacteria immediately after treatment and after 1 week of irradiation. Conclusion: Er,Cr:YSGG laser at high output power (2 W) detected a maximum reduction of E. faecalis in the infected root canals, but bacteria were not eliminated completely.