Purpose:
The purpose of this study was to determine the bond energy of three indirect restorative composite veneering materials to Yittrium stabilised zirconia (YZr) by using the strain energy release rate testing method.
Materials and methods:
Three indirect composite veneering materials (Ceramage – Shofu Inc; Signum - Heraeus Kulzer GmbH; Sinfony- 3M ESPE) were bonded to YZr plates with and without sandblasting and manufacturer’s recommended bonding agents. Utilising the method described by Cheng et al. (1999), a 12mm composite rod was bonded to a YZr plate with two opaque layers at the bond surface interface then, brought to failure using a universal testing machine. G-values were calculated. One-way ANOVA and Dunnetts’s tests (P = 95%) were performed. Homogeneity of the variables was confirmed with Bartlett’s test.
Results:
No significant difference in G-values was observed between the control groups of Ceramage, Signum and Sinfony. Within the Ceramage group, there was no significant difference between the surface treatments. In the Signum group no significant difference was observed between the control and sandblasted groups as well as between the sandblasted surfaces in combination with the bonding agent group, but no significant difference between the control and bonding agent alone was observed. In the Sinfony group, no significant difference was observed between the control and sandblasted groups, but a significant difference was observed between the control and sandblasted with bonding agent groups.
Conclusion:
The application of acidic functional phosphate monomer MDP or silicatising the YZr surfaces before veneering with indirect composite veneering material, resulted in higher bond energy results. Sandblasting the YZr surfaces with 120grit AlO2 only, did not increase the bond energy. The elastic modulus of the composite material influenced the bond energy required for detachment from to the YZr substructure.
