Comparison of Shear Bond Strengths of Conventional Resin Cement and Self-adhesive Resin Cement bonded to Lithium Disilicate: An in vitro Study.

Abstract

The aim of this study is to compare the shear bond strengths of conventional resin cement and self-adhesive resin cement bonded to lithium disilicate. A total of 40 extracted human molar teeth were mounted in self-cure acrylic resin. Teeth were prepared to obtain flat occlusal surface. About 40 lithium disilicate specimens of dimension-10 mm in diameter and thickness of 2 mm-were fabricated using lost wax technique. The samples were divided into four groups: Groups I, II, III, and IV (n = 10). The specimens were surface treated with Monobond S silane coupling agent. Self-etching primer and bonding agent were applied on the bonding surface of the teeth in groups I and III. The specimens were bonded to the primed teeth with the Multilink N resin cement and subjected to the universal testing machine. The specimens were light-cured. Specimens in groups II and IV were luted to teeth using self-adhesive cement RelyX U100. The same force was applied over the specimen as mentioned above. Excess cement was removed, and light curing was done. The specimens in groups III and IV were subjected to thermocycling for 10,000 cycles at temperatures altering between 5°C and 55°C. The shear bond strengths of conventional resin cement and self-adhesive resin cement with lithium disilicate were tested before and after thermocycling. Results indicated that thermocycling has no significant effect on the bond strengths of conventional or self-adhesive resin cement. However, from the study, it is seen that conventional resin cement had a higher shear bond strength value than the self-adhesive resin cement. There was a significant difference between the average shear bond strength values of conventional resin cement (Multilink N) and self-adhesive resin cement (RelyX U100) when bonded to lithium disilicate disks, and thermocycling had no significant effect on the bond strength of conventional or self-adhesive resin cements. Among all-ceramic systems available, lithium disilicate materials have emerged as an excellent esthetic material for fabrication of anterior and posterior crowns and three-unit anterior fixed partial dentures because of their high translucency and improved optical properties. For successful clinical outcomes, the luting agent should have high bond strength not only to the ceramic surface, but also to the tooth surface.