Comparison of the bond strength of composite resin to Er:YAG laser irradiated human enamel pre-treated with various methods in vitro

Background and Objective: We have reported that the application of ultrasonic scalers on the Er:YAG laser-irradiated enamel surface achieved bond strengths of approximately 16 MPa. However, it is reported that a bond strength of 20 MPa is needed to prevent the maginal gaps, so the tensile bond strength (TBS) of composite resin to the Er:YAG laser-irradiated enamel is still insufficient. Study Design/Materials and Methods: Various methods (phosphoric acid etching, air scaling, ultrasonic scaling, air powder polishing, combination with phosphoric acid etching, and prior mechanical removal methods) were tested as a technique to increase TBS of composite resins to the Er:YAG irradiated enamel. Results: Both the methods of mechanical removal following Er:YAG laser irradiation and the phosphoric acid etching following irradiation and mechanical removal had significant effects on TBS. TBS in the group with acid etching following air powder polishing showed highest value, 22.0 MPa. Conclusion: The application of phosphoric acid etching following mechanical removal of Er:YAG laser irradiation was effective to achieve high bond strength. (C) 2002 Wiley-Liss, Inc.