Comparison of Micro-Shear Bond Strength of Resin Cement to Zirconia With Different Surface Treatments Using Universal Adhesive and Zirconia Primer

Introduction: Increased demand for metal free fixed partial denture in recent years led to the developing of all ceramic material with excellent mechanical properties. One of the most popular all ceramic is zirconia which shows poor bonding properties. Recently, universal primer contains of silane and phosphate monomer for bond to zirconia have been introduced. The aim of this study is determination of the best method for bonding to zirconia based on the selection of the correct primer, suitable adhesive and best surface pretreatment. Methods: In this in vitro experimental study 16 sintered-zirconia blocks prepared in dimension of (18x6x2 mm) by CAD/CAM technology. Sample cleansed by ultrasonic device contain of 96% ethanol in 6 minutes, after air-drying, based on surface treatment randomly divided into 4 groups which each group divided into 2 sub-groups based on the use of a primer or universal bond: (1) no treatment: (a) cement + zirconia primer, (b) cement + universal bond. (2) Alumina pretreatment: (a) cement + zirconia primer, (b) cement + universal bond. (3) Cojet sand pretreatment: (a) cement + zirconia primer, (b) cement + universal bond. (4) laser pretreatment (a) cement + zirconia primer, (b) cement + universal bond. Composite disc prepared with condensation of composite resin in Tygon tube with integral diminution of 0.7 mm which cured for 40 sconds. Universal bond or zirconia primmer apply on the surface of the zirconia samples then cemented to composite disks by Panavia F2 according manufacture instructions. Micro-shear bond strength determined with universal testing machine. Failure mode assessed under stereomicroscope. Selected sample based on surface treatment evaluated under SEM. Data were analyzed using one-way analysis of variance (ANOVA). Results: Comparison of the 4 surface treatment groups revealed a significant difference and the highest bond belonged to Cojet and the lowest one to laser group. Conclusion: It seems that Universal Adhesive can to be considered as an alternative to bond to zirconia but the Cojet method is still required.