Abstract
Purpose: This study evaluated and compared the effects of different approaches for bonding composite resin to zirconia and determined the influence of aging in artificial saliva compared with distilled water on the composite resin shear bond strength to zirconia. Material and Methods: One hundred twenty zirconia square specimens (5 x 5 x 2 mm) were fabricated and randomly divided into six groups: zirconia bonding surface was left without treatment (NA, the control group); zirconia bonding surface was treated with 10-MDP containing primer only (Primer group); zirconia bonding surface was treated with intraoral air abrasion device (SAND group); the same procedures were used as for the primer group with MDP-containing primer (SAND-Primer group); zirconia bonding surface was treated with (TBS) coating (TBS group); and the same procedures were used as for the TBS group with MDP-containing primer (TBS-Primer group). All specimens received one coat of adhesive resin. The resin composite was then bonded using acrylic plastic tubes. Each group was divided equally (n = 10) according to the storage solution: distilled water or artificial saliva. Shear bond strength was tested using a universal testing machine. Failure modes were examined under original magnification x25. Results: Using TBS coating with MDP-containing primer is the most effective technique among all the groups, with (12.07 +/- 0.7 MPa) and (13.9 +/- 0.4 MPa) for distilled water and artificial saliva, respectively. The least effective was the control (NA) group (1.02 +/- 0.3 MPa) and (2.81 +/- 0.2) for distilled water and artificial saliva, respectively. The decrease in the bond strength for all surface treatments was significantly higher in distilled water than in artificial saliva. Failure modes were primarily adhesive. Conclusion: A combination of TBS coating with MDP-containing primer seems to offer the highest bond strength of composite resin to zirconia.