Shear bond strength of a denture base acrylic resin and gingiva-colored indirect composite material to zirconia ceramics

Purpose To evaluate the shear bond strengths of two gingiva-colored materials (an indirect composite material and a denture base acrylic resin) to zirconia ceramics and determine the effects of surface treatment with various priming agents. Methods A gingiva-colored indirect composite material (CER) or denture base acrylic resin (PAL) was bonded to zirconia disks with unpriming (UP) or one of seven priming agents (n = 11 each), namely, Alloy Primer (ALP), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB + Act), Metal Link (MEL), Meta Fast Bonding Liner (MFB), MR. bond (MRB), and V-Primer (VPR). Shear bond strength was determined before and after 5000 thermocycles. The data were analyzed with the Kruskal–Wallis test and Steel-Dwass test. Results The mean pre-/post-thermalcycling bond strengths were 1.0–14.1 MPa/0.1–12.1 MPa for the CER specimen and 0.9–30.2 MPa/0.1–11.1 MPa for the PAL specimen. For the CER specimen, the ALP, CPB, and CPB + Act groups had significantly higher bond strengths among the eight groups, at both 0 and 5000 thermocycles. For the PAL specimen, shear bond strength was significantly lower after thermalcycling in all groups tested. After 5000 thermocycles, bond strengths were significantly higher in the CPB and CPB + Act groups than in the other groups. Conclusions For the PAL specimens, bond strengths were significantly lower after thermalcycling in all groups tested. The MDP functional monomer improved bonding of a gingiva-colored indirect composite material and denture base acrylic resin to zirconia ceramics.