Durability of Resin Cement Bond to Aluminium Oxide and Zirconia Ceramics after Air Abrasion and Laser Treatment

Purpose: The erbium laser has been introduced for cutting enamel and dentin and may have an application in the surface modification of high-strength aluminum oxide and zirconia ceramics. The aim of this study was to evaluate the durability of the bond of conventional dual-cured resin cements to Procera Al2O3 and zirconium oxide ceramics after surface treatment with air abrasion and erbium laser. Materials and Methods: One hundred twenty Al2O3 and 120 zirconia specimens measuring 3 x 3 x 0.7 mm(3) were divided equally into three groups, and their surfaces treated as follows: either untreated (controls), air abraded with Al2O3 particles, or erbium-laser-treated at a power setting of 200 mJ. The surface of each specimen was then primed and bonded with one of two dual-cured resin cements (either SCP-100 Ceramic Primer and NAC-100 or Monobond S and Variolink II) using a 1-mm thick Tygon tube mold with a 0.75-mm internal bore diameter. After 24 hours and 6 months of water storage at 37 degrees C, a microshear bond strength test was performed at a crosshead speed of 1 mm/min. Surface morphology was examined using a confocal microscope, and failure modes were observed using an optical microscope. The data were analyzed using the Kaplan-Meier nonparametric survival analysis. Results: In the case of zirconia, air abrasion and Erbium: yttrium-aluminum-garnet (Er:YAG) laser treatment of the ceramic surface resulted in a significant reduction in the bond strengths of both resin cements after 6 months water storage; however, when the zirconia surface was left untreated, the SCP-100/NAC-100 group did not significantly reduce in bond strength. In the case of alumina, no treatment, air abrasion and Er: YAG laser treatment of the surface led to no significant reduction in the bond strengths of the three SCP-100/NAC-100 groups after 6 months water storage, whereas all three Monobond S/Variolink II groups showed a significant reduction. Conclusion: Er: YAG laser treatment of the zirconia surface did not result in a durable resin cement/ceramic bond; however, a durable bond between a conventional dual-cured resin cement and Procera All Ceram and Procera All Zirkon was formed using a ceramic primer containing the phosphate monomer, MDP, without any additional surface treatment.