Presently, the Er: YAG laser has received attention as a new cutting device with less noise and vibration, a reduced unpleasantness, less pain. The safety of dental pulp when the Er: YAG laser is applied to dentin has been confirmed. However, the denatured layer of dentin surface produced by Er: YAG laser irradiation caused lower resin bond strength. This communication summarizes the characteristics of the denatured layer of dentin, and introduces measures against the distur bance of resin adhesion produced by the denatured layer for better resin restoration. Also, the new procedure to remove dentin caries with an Er: YAG laser and an excavator is introduced.