Bond strength of zirconia ceramics applied with a pH-cycling modeland different repair methods

To evaluate the shear bond strength of yttria-stabilized zirconia (YSZ) ceramics based on the type of surface treatment, repair kit, and aging method used.

YSZ ceramic blocks (N = 120) measuring 6 mm x 8 mm x 8 mm were randomly and equally divided into three groups for different surface treatments: (a) surface treatments recommended by the manufacturer (control), (b) air abrasion, and (c) Er:YAG laser. After surface treatment, either the Cimara intraoral ceramic repair kit or the Bisco intraoral repair kit were used on the samples. A resin composite was incrementally applied to the treated surfaces and light cured. Repaired samples were aged using either thermocycling or pH cycling. A shear bond strength test was conducted on all samples, and failure patterns were examined under a stereomicroscope. Data were analyzed using three-way ANOVA, Kruskal-Wallis, Mann-Whitney U, and Bonferroni corrected paired comparison tests.

Interactions were found between aging methods, surface treatments, and repair kits, as well as between repair kits and surface treatments (P< 0.05). Although there was no statistically significant difference in bond strength values between the air abrasion and control groups in the thermal cycle (P= 0.053) and pH cycle (P= 0.104) for the Cimara repair kit, the bond strength values of the Er:YAG laser groups were statistically significant (P< 0.001). For the Bisco intraoral repair kit, there was a statistically significant difference in bond strength values between surface treatments in both aging methods (Plt; 0.001). All groups showed 100% adhesive failure.

The results of this study indicate the recommended use of the pH cycle aging method and primers containing carboxylic acid monomer and MDP for the repair of YSZ ceramics.