Effect of combining Gold Nanoparticles with Diode or Er. Cr:YSGG Laser on the Bond Strength of Etch- and- Rinse Adhesive to Dentin Surface

Background The aim of this work is to study the effect of different types of laser and gold nanoparticles on the bond strength of etched and adhesive dentin surface. Methods Sixty human molars were collected; the crowns were removed and a cavity (2x3 mm) was prepared on the buccal and lingual surfaces. Then, the teeth were sectioned perpendicularly to the longitudinal axis. The samples were divided according to the adhesive technique used and the hardness was tested by Vickers hardness tester, the roughness was tested by using universal testing machine and the depth of penetration was tested by Scanning electric microscope. Results Compared with those in the control group, the hardness in the groups treated with the laser was significantly greater. Moreover, for roughness, group C1 exhibited greater roughness than did the other groups. With respect to the depth of penetration, Group A0 and Group C0 demonstrated the greatest depth of penetration, while Group B0 and Group D0 demonstrated the lowest depth of penetration. Conclusions After applying the adhesive, the laser beam improved the diffusion of the material into the dentinal tubules in the presence of gold nanoparticles and increased the hardness and roughness of the dental structure.