The effect of repair protocols on shear bond strength to zirconia and veneering porcelain

The aim of this study was to evaluate the shear bond strength (SBS) of a new repairing material including zirconia primer to zirconia and veneering porcelain after various surface treatments. A total of 60 specimens (30 zirconia-Zr and 30 feldspathic porcelain-Feld) were prepared and divided into 6 groups (n = 10). Two surface preparations (air abrasion-AA and Erbium Yag (Er-YAG) Laser-Las) were applied to the specimens. Zr and Feld specimens treated with a grinding bur according to manufacturer advice, were used as control (C). Repair material (Cimara Zircon, VOCO, Germany) was applied to the specimens 2 mm in height. The SBS was measured in a universal testing machine at 1 mm/min crosshead speed. The SBS data (MPa) were analyzed using two-way ANOVA and Tukey HSD multiple comparison tests (α = 0.05). Significant effects of the material type (p = 0.005) and the surface treatment strategy (p = 0.000) were found. Interaction terms were also significant (p = 0.000). While the Zr-C (68,4 MPa) showed the highest SBS (p < 0.05), Zr-Las (16,4 MPa) had the lowest SBS (p < 0.05). The highest SBS value was obtained when both zirconia and veneering porcelain were treated with a grinding bur without any additional surface treatment.