Statement of The Problem: Debonding is considered as a common cause of failure in zirconia-based restorations. Despite that different resin cements and different surface treatment methods are used, the success rate is still of concern.
Purpose: The purpose of this study is to evaluate effect of luting agent type and surface treatment on bond strength to a zirconia-based ceramic. The following hypotheses that will be tested is that: surface treatment and resin cement selection influence the bond strength at the cement-ceramic interface. Materials and methods: In this study, 60 zirconia specimens were treated by two surface treatments (sandblasting and silica coating) then bonded to 60 composite specimens using three resin cements with different kinds of monomers (Bifix QM, Panavia F2.0 and Multilink Automix). Finally all of the specimens underwent aging by thermocycling before measuring the shear bond strength. Results: The highest shear bond strength values were recorded in the group treated by silica-coating (CoJet) and bonded by Panavia F 2.0. The lowest bond strength values were recorded in the group treated by air-particle abrasion and bonded by Bifix QM. Regardless to the resin cement used, totally it was found that CoJet group recorded statistically significant (P<0.05) higher shear bond strength value than air particle abrasion group. Regardless to the surface treatment, totally it was found that Panavia F2.0group recorded statistically significant (P<0.05) highest shear bond strength value followed by multilink automix group, then Bifix QM group. Conclusion: Within the limitations of this study, the following conclusion can be drawn: Surface treatment of zirconia surface with CoJet sand gives higher bond strength with the resin cements than 50 μm alumina air particle abrasion. Panavia F 2.0 resin cement gives higher bond strength to zirconia than Multilink Automix and Bifix QM.*