An in vitro evaluation of the long-term resin bond to a new densely sintered high-purity zirconium-oxide ceramic surface

Statement of problem: Successful long-term bonding to zirconia ceramic remains a challenge, requiring special cements and surface roughening by airborne-particle abrasion, which might negatively affect the ceramic. Purpose: The purpose of this study was to evaluate the shear bond strength (SBS) of composite resin cylinders to a modified zirconia surface using different luting techniques after thermal cycling. Material and methods: Composite resin (TPH3) cylinders with a diameter of 3 mm were bonded to zirconia ceramics (Procera Zirconia) with a modified surface (RZ) and a machined surface (MZ). Three different adhesive luting cements (Panavia F2.0, RelyX ARC, RelyX Unicem) in combination with and without airborne-particle abrasion (50-μm and 110-μm Al₂O₃) were used. RZ was bonded using all 3 cements with (50 μm) and without airborne-particle abrasion; with 110 μm, only Panavia F2.0 was used. MZ was bonded using only Panavia F2.0 with (50 μm, 110 μm) and without airborne-particle abrasion. SBS was tested in a universal testing machine (Instron) before and after 90 days of water storage and 20,000 thermal cycles (dwell time, 15 seconds). Statistical analysis was performed using a multifactorial ANOVA model with α=.05. Results: Mean SBS ranged from 10.1 to 20.0 MPa after 3 days and from 0.16 to 14.8 MPa after thermal cycling. Thermal cycling decreased SBS significantly. Airborne-particle abrasion significantly decreased SBS to the modified surface, regardless of cements used. SBS to the modified zirconia surface was significantly higher than to the machined surface. Conclusions: SBS to the modified zirconia surface is higher than to airborne-particle-abraded, machined zirconia. Airborne-particle abrasion of the modified zirconia surface is not recommended. (J Prosthet Dent 2009;101:29-38).