Evaluation of bond strength of zirconia ceramicsapplied with PH-cycling model and different repairmethods

Aim: The aim of this study was to evaluate the shear bond strength of Yttria Stabilized Zirconia (Y-TZP) ceramics treated with three different surface treatments (no treatment, air abrasion and Er:YAG laser) and repaired with two different repair kits (Cimara and Bisco) followed by aging with two different aging methods (pH cycling and thermocycling). Materials and methods: Y-TZP ceramic blocks(N=120) (Aidite, Zir Dental, Qinhuangdao, China) (6 mm x 8 mm x 8 mm) were randomly and equally divided into three groups for different surface treatments: (a) control group (surface treatments recommended by the manufacturer) (b) air abrasion, and (c) Er:YAG laser. After surface treatment, one of the following repair kits was applied to the blocks: (1) Cimara (Voco, Cuxhaven, Germany) and (2) Bisco Intraoral Repair Kit (Bisco, Schaumburg, IL, USA). Resin composite (Clearfil Majesty Posterior, Kuraray, Japan) was applied to the treated surfaces incrementally and light cured. Half of the repair samples were subjected to thermocycling (n=10) (5.000 cycles) and the other half to pH cycling (n=10) (6 months), and then shear bond strength test was applied to all specimens. Failure patterns were examined under a stereomicroscope. Data were evaluated by using three-way analysis of variance, Kruskal-Wallis, Mann-Whitney U and Bonferroni corrected paired comparison tests (α=0,05). Results: Interactions were found between aging methods, surface treatments and repair kits, as well as between repair kit and surface treatments (p<0,05). All groups showed 100% adhesive failures. Conclusion: It has been observed that surface treatments, repair kits and pH cycle have an effect on shear bond strength in repair of zirconia ceramics.