Influence of Er:YAG Laser on Cavity Preparation and Surface Treatment in Microleakage of Composite Resin Restorations

OBJECTIVE: The purpose of this study was to assess microleakage on class V cavities prepared by Er:YAG laser with varying surface treatment. BACKGROUND DATA: There has been little reported research on microleakage at cavities prepared and treated with Er:YAG laser. METHODS: Fifty preparations using Er:YAG laser or a highspeed handpiece were developed. The surface treatment was performed as follows: Er:YAG laser (group 1); 35% phosphoric acid (group 2); laser + acid (group 3); finishing with low-speed + laser + acid (group 4); conventional preparation developed with a high-speed handpiece + acid (group 5--control). The samples were restored with Single Bond/Z250, thermocycled, isolated, and immersed in a 50% AgNO(3) solution. The restorations were sectioned, and the microleakage was measured in milimeters using a specific computer software. Data were analyzed employing ANOVAand Tukey test. RESULTS: Statistical analysis showed that group 5 (G5) obtained the lowest results of microleakage (22.05%), and it was statistically similar (p > 0.05) to G1 (37.7%) and different (p < 0.05) from the other groups (G2 = 50.4%; G3 = 43%; G4 = 44.2%). The occlusal margins (22.62%) demonstrated less microleakage (p < 0.05) than the cervical margins (56.32%). CONCLUSION: The use of Er:YAG laser for cavity preparation and surface treatment negatively influenced the marginal sealing of composite resin restorations.