Evaluation of antimicrobial and thermal effects of diode laser on root canal dentin

The aim of this study was to evaluate the antimicrobial effects of diode laser and temperature rise on the root surface during application.

Thirty-six teeth were chemomechanically prepared and irrigated with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid, and then autoclaved and incubated with a suspension of Enterococcus faecalis. The specimens were randomly divided into three groups (n = 12): Group 1, irradiated by diode laser at 1.2 W; Group 2, irradiated by diode laser at 2 W; and Group 3, irradiated by diode laser at 3 W. The grown bacteria were counted and the mean numbers of the each test tube were determined. The temperature was measured on the external apical third of the root during laser application. The mean values of results for each group were compared using one-way analysis of variance and Tukey test.

No significant difference was obtained among the test groups in terms of the colony counts (P > 0.05). According to the temperature changes, there was a significant difference between groups (P < 0.05). Temperature rises were 16.79°C, 10.20°C, and 6.25°C in Group 3, Group 2, and Group 1, respectively.

Diode laser irradiation with 1.2 W demonstrated comparable performance with 2 W and 3 W power sets for elimination of E. faecalis from root canal with less temperature rise.