Effects of Hot Chemical Etching and 10-Metacryloxydecyl Dihydrogen Phosphate (MDP) Monomer on the Bond Strength of Zirconia Ceramics to Resin-Based Cements

Purpose: The purpose of this in vitro study was to evaluate the hot chemical etching method on the shear bond strength between zirconia and two resin cements. Materials and Methods: Sixty zirconia specimens (13 x 7.5 x 2.5 mm(3)) were prepared and treated as follows: (1) airborne-particle abrasion with 50 m Al2O3 particles; (2) hot chemical etching for 10 minutes; (3) hot chemical etching for 30 minutes. Sixty composite cylinders of 3 mm diameter and height were prepared and bonded to zirconia specimens, which were divided into subgroups A and B. Group A: cemented with conventional resin cement (Variolink II); group B: cemented with 10-metacryloxydecyl dihydrogen phosphate (MDP) monomer containing resin cement (Panavia SA) after the application of surface treatments. Next, the specimens were stored in 37oC distilled water for 24 hours. Following water storage, shear bond strength test was performed at a 1 mm/min crosshead speed in a universal testing machine. The statistical analyses were performed with one-way ANOVA and post hoc Tukey tests. p < 0.05 was considered statistically significant. Results: The results from all of the tested groups exhibited lower shear bond strength values than group II-B and higher shear bond strength values than group I-A (p < 0.05). Conclusion: The use of the hot chemical etching method for 10 minutes increased the shear bond strength of zirconia ceramics to both conventional and resin cements and seems to be an effective method. The MDP monomer-containing resin cement, Panavia SA, improved the resin bonding of zirconia ceramics when combined with airborne-particle abrasion.