Bond Durability of Three Bonded Resin Cements to Zirconia Substrate
Objectives: The goal of this study was to evaluate the bond durability of three bonded resin cements including NX3 (Kerr), Multilink Automix NG (Ivoclar Vivadent), and Panavia V5 (Kuraray), when bonded to zirconia (3M ESPE Lava™).
Methods: Dental substrates were embedded in cold-cure acrylics. The substrates were polished with 240-grit and 600-grit SiC paper, and then sandblasted with 50 mm Al3O3 powder at 60 psi. Each cement was bonded to the prepared substrate’s surface with either a ceramic primer or an adhesive per IFU. Shear bonding test specimens were prepared using a cylindrical mold (D=2.38mm) and tested following ISO 29022. Each cement was allowed to self-cure. The specimens (n=6) were then stored in DI-water at 37°C for 24 hours first and then either (i) debonded (initial SBS) or (ii) further subjected to thermal-cycling (TC, 5,000 cycles of 5°C/55°C) and then debonded. The bond durability of each cement product was evaluated by comparing initial SBS with SBS after TC. Results: One-way ANOVA analysis (p<0.05) was conducted to study the statistical difference among the groups. ANOVA analysis revealed that 1) the initial SBS of the three cementation systems are not statistically different from each other; 2) after TC, the SBS of NX3/XTR is statistically higher than Multilink/Monobond Plus or Panavia V5/Clearfil ceramic primer; 3) the SBS of NX3/XTR experienced minimal SBS loss (8.5%) after TC while both Multilink/Monobond Plus and Panavia V5/Clearfil ceramic primer experienced substantial SBS loss (35.8% and 26.0%) after TC. Conclusions: NX3/XTR adhesive exhibited superior bond durability to zirconia among three cementation systems studied. Both Multilink/Monobond Plus and Panavia V5/Clearfil ceramic primer experienced substantial decrease in bond strength after thermocycling. Furthermore, the GPDM-based XTR adhesive is proven to be effective as a zirconia primer.