Effect of Er:YAG Laser Etching on the Shear Bond Strength and Microleakage of Self-Glazed Zirconia Ceramics.

Abstract

Objective: To investigate the effect of Er:YAG laser irradiation on the shear bond strength (SBS) and microleakage of self-glazed zirconia (SZ) ceramics. Background: SZ is a novel type ceramic; laser irradiation has started to be used in the surface treatment of different ceramics, while SZ has been rarely studied to improve the bond quality. Methods: One hundred twenty blocks (5 mm × 5 mm × 5 mm) of SZ ceramics were produced and split into eight groups following different surface treatments (n = 15): Group A: no treatment; Group B: standard grid processing; and Group C-H: different Er:YAG laser power settings (100, 200, 300, 400, 500, and 600 mJ). Ten blocks of each group received the measurement of SBS and fracture mode analysis, three blocks underwent the evaluation of the microleakage depths, and the other two blocks were observed under the scanning electronic microscopy (SEM). Results: Group F obtained the highest SBS and the lowest microleakage depth without damaging the ceramic surface structure, which was statistically significant compared with the control group and gridding group (p < 0.05), whereas the difference was not statistically significant (p > 0.05) between group E and group F. The results of bonding performance were consistent with failure types and observation of surface characterizations in SEM images. Conclusions: According to the results here, Er:YAG irradiation had effect on surface treatment. In addition, 400 mJ Er:YAG could increase the SBS and decrease the microleakage depth on SZ ceramics without damaging the surface structure.