Effect of Polymerization Time and Thickness of Monolithic Zirconia on the Bond Strength of Self-Adhesive Resin Cement

Abstract

Background and Aim Self-adhesive resin cements are commonly used to lute zirconia restorations. The bond strength between the resin cement dentin and the ceramic material depends upon the degree of conversion of the cement during polymerization. This study was aimed to determine the optimal curing conditions in order to maximize the bond strength between self-adhesive resin cement and highly translucent monolithic zirconia crowns.Method Fifty-two pre-sintered highly translucent zirconia discs of diameter 10 mm each were milled from commercially available blocks Dent Gallop SHT and were grouped into two Group A 1.5 mm thickness Group B 2 mm thickness. Preformed polyethylene moulds were used to fabricate cylinders made of composite resin having a diameter of 6 mm and height 3 mm each. These were cemented onto zirconia discs using self-adhesive resin cement Kerr Maxcem Elite and were cured. Group A and B were divided into two subgroups of 13 samples each based on the curing time of the resin cement. Group A1 was cured for 10 seconds and Group A2 for 20 seconds. Group B1 was cured for 10 seconds and B2 was cured for 20 seconds. The specimens were embedded into resin stamps of 1x1 cm and subjected to shear load test.Results One-way ANOVA was used to compare the mean shear bond strength. The 1.5 mm highly translucent zirconia cured for 20 seconds showed highest and 2 mm cured for 10 seconds showed the least strength.Conclusion The study concluded that highly translucent zirconia reduces the curing light attenuation and when curing time is increased within the limits the shear bond strength of resin cement increases.