The purpose of this study is to research the change of mechanical properties of dental enamel around the laser irradiated area. CO2 laser and Er: YAG laser were irradiated bovine enamel at 23-161J/cm2, and the its fracture toughness was examined by means of indentation microfracture method.
The fracture toughness of bovine enamel irradiated by CO2 laser was reduced compared with control at any irradiation energy. On the other hand Er: YAG laser irradiation at all energy condition did not cause the reduction of the fracture toughness.
These result suggest that Er: YAG laser is useful in preparation of tooth without mechanical changes of enamel around irradiated area.
