Results: Laser with energy of 2-6 W and irradiating distance below 2 mm could effectively remove the smear layer from the dentin. Dentinal tubule orifices were minished or partly blocked. With the energy of irradiation increased, the elimination of the intertubular dentin increased; 结果:照射距离<2mm,2~6W能量的激光均能有效去除牙本质表面玷污层,牙本质小管管径减小或部分封闭,随着能量增高,管间牙本质去除逐渐增多;