Effect of Adhesive Resin Type for Bonding to Zirconia Using Two Surface Pretreatments

This laboratory study evaluated the short-term adhesive properties of one 10-MDP-containing and two MDP-free resin composite cements, using two types of zirconia surface pretreatments.

Eighteen sintered zirconia disks (Procera, Nobel Biocare) were randomly divided into three study groups according to their surface treatment: (a) polished surface (control group); (b) airborne-particle abraded (grit blasted) with 50-μm aluminum trioxide (APA); and (c) selective infiltration etching (SIE). The zirconia disks were then bonded to 180 pre-aged composite resin disks (0.9 mm×0.7 mm) using three different resin composite cements (Panavia F2.0, Esthetic, and Aegis). Resin-zirconia adhesion strength was evaluated using the microshear bond strength test (μSBS) after 24 h (baseline) and 2 weeks of storage in deionized water at 37°C. Three-way ANOVA, one-way ANOVA, and Scheffé's post-hoc tests were used to analyze the data (p=0.05).

Surface treatments significantly influenced the μSBS (p<0.001). The highest mean μSBS values were recorded with the MDP-containing resin composite cement (Panavia F2.0) in both SIE (32.4±5.3 MPa) and APA (28.6±8.8 MPa) groups. Water storage significantly reduced the bond strength obtained with the MDP-free cements (Esthetic and Aegis) and in the control group, while the bond strength in SIE and APA groups using the 10- MDP-containing resin composite cement exhibited relatively unchanged values.

SIE and APA in combination with the 10-MDP-containing resin composite cement established a strong, durable bond to zirconia substrates under short-term aging conditions. The cement containing amorphous calcium phosphate (Aegis) did not bond to zirconia surfaces. During the observation period, μSBS decreased significantly due to hydrolytic degradation, except when the 10-MDP-containing resin composite cement (Panavia F2.0) was used in the SIE and APA groups.