Effects of Various Laser Treatments on Surface Characterization and Repair Bond Strength of Zirconia-Reinforced Lithium Silicate Ceramics.

Abstract

To evaluate the effects of two different lasers and their use in combination with hydrofluoric acid (HF) etching on the surface roughness of zirconia-reinforced lithium silicate (ZLS) ceramics and their shear bond strength (SBS) to composite resin. The five study groups were as follows: (1) Group H = HF etching; (2) Group N = Nd:YAG (neodymium: yttrium-aluminum-garnet) laser; (3) Group NH = Nd:YAG laser + HF gel; (4) Group E = Er:YAG (erbium: yttrium-aluminum-garnet) laser; and (5) Group EH = Er:YAG laser + HF gel. Surface roughness was assessed using a noncontact profilometer, and SBS tests were conducted with a universal testing machine. The mean SBS values were 16.23 ± 1.77 MPa for Group H, 17.1 ± 1.65 MPa for Group N, 16.65 ± 1.11 MPa for Group NH, 8.08 ± 1.12 MPa for Group E, and 11.58 ± 0.82 MPa for Group EH. There were significant differences between groups E and EH (P < .001) but no significant differences (P > .05) among the other groups. Clinicians may prefer Nd:YAG laser or the combination of Nd:YAG and HF to intraorally repair fractured areas.