Purpose: To evaluate the effects of bleaching combined with Er:YAG laser or Nd:YAG laser on bond strength and microleakage of resin fillings on enamel surface.
Methods: Sixty-four pieces of enamel specimens prepared from isolated teeth were randomly divided into 4 groups(n=16): control group, simple bleaching group, bleaching combined with Er: YAG laser group and bleaching combined with Nd:YAG laser group. Then the shear bond strength and the depth of microleakage were tested, and the fracture mode of the specimen was observed under microscope. SPSS 26.0 software package was used for statistical analysis.
Results: After bleaching simply, the bond strength of the restoration was significantly decreased, and the marginal microleakage was significantly increased(P＜0.05). There was no significant difference in shear bond strength and microleakage depth between the group bleaching combined with Er: YAG laser and control group(P＞0.05). The shear bond strength after bleaching combined with Nd:YAG laser was significantly reduced (P＜0.05), but there was no significant difference in the depth of microleakage compared with unbleached microleakage(P＞0.05). Bonding interface fracture was the main fracture mode for all groups.
Conclusions: Compared to traditional bleaching, bleaching combined with laser has certain clinical advantages due to its less influence on bond strength and microleakage of resin fillings.