Shear Bond Strength of Cement to Zirconia

This study investigated the shear bond strength (SBS) of various cements to zirconia ceramic. CoCr-cylinders were bonded to zirconia plates (20 mm x 10 mm x 2 mm; n = 8 per group) using four self-adhesive resin cements (one capsule, three hand-mixed) and four resin cements, partly in combination with a tribochemical/ silane treatment. All cements were auto-polymerizing. The bonding areas were sandblasted using 110 mu m Al(2)O(3). The shear bond strength was determined after 24 h, 30 days, 90 days of water storage (37 degrees C) and after 12 000 thermal cycles. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Bonferroni post hoc test (alpha = 0.05). After 24 h and after thermal cycling (TC) the lowest value of shear bond strength was found for the control Variolink without bonding pre-treatment (9.5 MPa/3.1 MPa) and the highest results were determined for Calibra with bonding pre-treatment (37.3 MPa/31.9 MPa). After 30 days and 90 days of storage in water the highest SBS values were found for RelyX (33.3 MPa/28.6 MPa), and again lowest values were determined for Variolink (8.8 MPa/9.1 MPa). After 90 days storage all samples of Maxcem failed. The groupwise comparison revealed significantly different SBS results between 90 days storage and the initial results after 24 h (p = 0.003). No significant differences were found between the other storage conditions (p > 0.057). The systems without bonding pre-treatment provided significantly lower SBS in comparison to the self-adhesive systems and the systems with bonding pre-treatment (p = 0.000). Within the limitations of this study, three of four self-adhesive bonding systems provided bond strengths to zirconia, comparable to systems with additional bonding pre-treatment. The durability of the bonding resin and zirconia can only be judged after long-term water storage. (C) Koninklijke Brill NV, Leiden, 2009