Effect of surface treatments on the bonding strength of self-adhesive resin cements to zirconia ceramics

Objective: To investigate the effect of surface treatments on the surface properties of yttria-stabilized zirconia ceramics (Y-TZP) and the interfacial bond strength to self-adhesive resin cements. Method and Materials: Two types of Y-TZP (Vita In-Ceram YZ [VZ] and IPS e.max ZirCAD [IZ]) were used. The specimens were divided into four groups in each test according to the surface treatment used: Group A (control; no treatment), Group B (airborne-particle abrasion), Group C (CH2Cl2 for 60 minutes), and Group D (hot etching for 60 minutes). Scanning electron microscopy, atomic force microscopy, and X-ray diffractometry were carried out. Two types of self-adhesive resin cements (i CEM [IC] and Multilink Speed [MS]) were used for testing the adhesion. The G-value (J/m2) was measured with a four-point bending configuration. Following fracture testing, specimens were examined with a stereomicroscope. Data were analyzed using ANOVA and Tukey test. Results: IZ treated with hot etching showed the highest average surface roughness values (172.5 ± 15.43 nm) compared with the other groups (P .05). The greatest amount of monoclinic phase was measured after airborne-particle abrasion for VZ (8.9%), followed by IZ (6.1%). Improvements in bond strength values were found in the following order: hot etching > CH2Cl2 > airborne-particle abrasion > no treatment. Most failure modes were adhesive type of failures between ceramics and cement material (68.76%). Conclusion: Adhesion between Y-TZP and self-adhesive resin cements can be improved by the use of CH2Cl2 or hot etching surface treatments prior to resin cement application as an alternative technique to airborne-particle abrasion treatment. Keywords: adhesion, atomic force microscopy, self-adhesive resin cement, surface treatments, X-ray diffractometry, Y-TZP ceramic