Effect of different surface treatment methods on the shear bond strength of zirconia based restorations

Statement of the Problem: Delamination of zirconia-veneered restoration is considered to be a very common failure in clinical practice. Therefore, using a chair side intra-oral repair option may be a simple alternative method to the total replacement of the restoration and may provide a clinically-acceptable and reliable immediate solution.
Aim of the Study: This study evaluated the shear bond strength of two different repairing systems (CoJet and Ceramic repair N) of zirconia-based restorations and evaluated the effect of high and low sandblasting pressure on the shear bond strength between zirconia and composite resin.
Materials and Methods: Thirty zirconia specimens were divided into two main groups according to the repairing systems: Group CJ: CoJetTM repairing system [chairside silica coating with 30 µm SiO2 + silanization + adhesive] (3M ESPE) (15 specimens). Group CR: Ceramic Repair N system (Ivoclar Vivadent) [grinding with diamond stone + Monobond N universal primer adhesive] (15 specimens). Each group was further sub-divided into three sub-groups according to the surface treatment methods: Sub-groups (CJS 3, 2,1): CoJet Sandblasting at pressure 3,2,1 bar, Sub-group (CRG): Ceramic Repair Grinding with diamond stone and Sub-groups (CRS 2,1): Ceramic Repair Sandblasting with CoJet sand at pressure 2 and1 bar. Tetric N- ceram composite resin was polymerized on each conditioned specimen. The shear bond strength was tested using a universal testing machine, and fracture sites were examined with SEM. The data of bond strengths were statistically analyzed with two-way ANOVA.
Results: No statistically significant differences in the mean shear bond strength values between Cojet Group (11.31± 0.71 MPa) and Ceramic Repair-N Group (11.02± 0.81 MPa). There were no statistically significant differences in the mean shear bond strength values between 1 bar treated sub-group (11.13± 1.4 MPa), 2 bar treated sub-group (11.23± 1.5 MPa), grinding sub-group and 3 bar (control) sub-group (11.12±1.8MPa), (P>0.05).
Conclusion: Surface treatment of low pressure abrasion protocol or grinding following with Monobond N universal primer gave the similar shear bond strength values of the high pressure abrasion protocol.