Bonding Between Primed Zirconia and Composite Using Self-adhesive Resin Cement

Objectives: This study assessed the influence of alumina-blasting (AB) and adhesive primer (AP) on the shear bond strength of self-adhesive resin cement between zirconia and dual-cured resin composite for core build-up. Methods: The specimens were divided into 18 groups with three dual-cured self-adhesive resin cements {Maxcem Elite (ME, Kerr), RelyX Unicem Clicker (RUC, 3M ESPE) G-Luting (GL, GC)}, three different surface treatments {non-treatment (NT), AB, and AB+AP (Metal Primer II (GC)}, and two thermal cyclings (TC). The dual-cured resin composite (Unifil Core EM, GC) disk specimens were also prepared using laboratory-curing unit. The zirconia (GC) specimens were treated with one of three methods, bonded to resin composite with one of three resin cements, and then photo-polymerized with a visible-light-curing unit. Specimens were stored in water at 37ºC for 24 hrs and/or thermocycled 20,000 times before shear bond strength testing. Means and SDs (in parenthesis) of shear bond strength (MPa) are listed in Table. Data were analyzed by three-way ANOVA and identical letters were not significantly different by Tukey Compromise test (p>0.05, n=7). Results: At TC 0, AB and AB+AP were significantly effective for improving shear bond strength of self-adhesive resin cement between zirconia and resin composite compared with NT. All groups except treatment with AB+AP and bonding with GL, decreased significantly shear bond strength after TC 20,000. Conclusion: These results suggest that the treatment of alumina-blasting followed by application of adhesive primer on the zirconia surface is preferable to obtain durable bonding of dual-cured self-adhesive resin cement between zirconia and resin composite.