Effects of different ER,CR:YSGG laser parameters on resin-enamel/dentin bond strength

The purpose of the present study was to evaluate microtensile bond strength of a microhybrid resin composite restorative materials, which is used with an etch-and-rinse adhesive to enamel and dentin after treatment with Er,Cr:YSGG laser with different output power and pulse frequency combination. Resin-dentin/enamel interfaces also evaluated under SEM. Enamel (E) and dentin (D) samples were prepared from bovine incisors. Following immersion of teeth in the acrylic blocks and flattening surfaces, samples were divided into 8 subgroups as following (n=5): E-Control (no treatments), E-Bur (mechanical roughening was performed using high-speed diamond bur), E-Laser 6W-20Hz, E-Laser 6W–35Hz, E-Laser 6W–50Hz, E-Laser 3W-20Hz, E-Laser 3W–35Hz, E-Laser 3W–50Hz; D-Control (no treatments), D-Bur (mechanical roughening was performed using high-speed diamond bur), D-Laser 3W-20Hz, D-Laser 3W–35Hz, D-Laser 6W–50Hz, D-Laser 1.5W-20Hz, D-Laser 1.5W–35Hz, D-laser 1.5W–50Hz. Following acid-etching all surfaces, composite build-ups were done. Samples were cut into resin-enamel/dentin sticks with dimensions of 0.8 mm2 and microtensile bond strength test was performed. E-Laser 3W-50Hz (36.22±6.0 MPa) showed significantly highest bond strength with exception of E-Control (32.85±9.8 MPa). For dentin, D-Control (27.70 ± 7.0) and D-Bur (24.98 ± 8.8) showed significantly different bond strengths from all laser groups. As a conclusion, laser irradiation could enhance or impair the microtensile bond strength to depending to the tooth structure and laser parameters used. Tested laser parameters, which did not impair resin bond strength with enamel, reduced resin bond strength with dentin.