Shear bond strength of ZrO2 ceramic material and luting cements

The aim of this study was to test the influence of different pretreatmens of ZrO2 ceramic core material on the shear bond strength to various type of resin cements.

Methods: The material for the study comprised the 128 ZrO2 based ceramic specimens (Zeno Tec System, Wieland, Germany) obtained through CAD/CAM procedure, divided into two equal experimental groups according to different pretreatmen techiques: etching with 4,9% HF and blasting with tribochemical silica layer (CoJet, 3M ESPE). Four resin based cements served for luting procedure: dual cured Variolink II (Ivoclar-Vivadent, Liechtenstein), Panavia F (Kurarey, Japan), and selfadhesive RelyX Unicem (3M ESPE) and Maxcem (Kerr Hawe) The complex specimens, combinations of ceramic material-luting cement, were prepared in originally designed device for testing. The shear bond strength were measured with a universal testing machine (Instron Corp, model 1332, Norwood) of a 5 kN load cell operating at a crosshead speed 0.5 mm/min.

Results: The results obtained, pointed out that the blasting with CoJet was the most effective surface treatment for ZrO2 ceramic material. According to that, the mean value of shear bond strength in the second group was the highest for Maxcem and Panavia F (32.04±7.25 MPa, 32.17±10.05 MPa) and the lowest for Variolink II (23.48±7.67 MPa). For the first group, all values were lower, in range between 6.38±1.67MPa for RelyX Unicem to 22.00 ±4.42MPa for Panavia F.

Conclusion: a.) blasting the ZrO2 core material with CoJet device is more efficient treatment than etching with HF acid, and b.) Panavia F dual cured resin cement showed the strongest bond to ceramic core.