Efficacy of Er:YAG laser irradiation in removing debris and smear layer on root canal walls.

The purpose of this study was to evaluate the efficacy of Er:YAG laser irradiation in removing debris and smear layer from prepared root canal walls. Thirty-six human extracted mandibular incisors teeth were divided into three groups. Group 1 (G1) was control specimens that were not lased. The teeth of group 2 (G2) and group 3 (G3) were irradiated by Er:YAG laser at different watt powers of 1 W and 2 W. The teeth were bisected and prepared for study in stereoscopic light microscope and SEM. Control specimens showed an amount of debris and heavy smear layer obscuring the dentinal tubules at all levels in the canals. The root canal walls irradiated by Er:YAG laser were free of debris, with an evaporated smear layer and open dentinal tubules. Statistical analyses showed significant differences (p < 0.01) in cleanliness smear layer between G1 and G2, and G1 and G3. However, there was no statistically significant difference between G2 and G3 in the cleanliness of the middle and apical one-third of the root canals. These results show Er:YAG laser is effective in removing debris and smear layer from root canal walls.