METHODS:Human enamel blocks were irradiated with pulsed Nd:YAG laser at different energy . The surface hardness and abrasion rate of enamel were examined before and after laser irradiation. Morphological changes of enamel were observed with SEM.

• 方法 :用不同剂量的脉冲Nd :YAG激光照射人牙釉质 ,测量照射前后釉质硬度及磨耗率的改变 ,并用扫描电镜观察釉质表面形态的变化。