INTRODUCTION: The aim of this study was to investigate the Scanning Electron Microscope (SEM) analysis of tooth surface irradiated by different parameters of Er:YAG laser.METHODS: 15 caries-free extracted human third molars were used in this study. The teeth were put into 5 groups for laser irradiation as follows: Group 1 (power: 2.5 W, Energy: 250 mJ); Group 2(power: 3 W, Energy: 300 mJ); Group 3 (power: 3.5 W, Energy: 350 mJ); Group 4 (power: 4 W, Energy: 400 mJ); Group 5 (power: 4.5 W, Energy: 450 mJ). All samples were prepared by repetition rate of 10 Hz. Then,the samples were prepared for SEM examination.RESULTS: The SEM images showed cleaned ablated surface and exposed dentinal tubules, without production of smear layer.CONCLUSION: It can be concluded that Er:YAG laser can be an alternative technique for surface treatment and can be considered as safe as the conventional methods,like turbine and bur
