Evaluation of Shear Bond Strength of Composite Resin to Dentin after Etching with Er,Cr:YSGG Laser And Conventional Acid Etch (An In Vitro Study

Abstract

The aim of this study was to evaluate shear bond strength of composite to dentin after etching with conventional acid, Er,Cr:YSGG laser and Er,Cr:YSGG laser in conjunction with acid. Thirty recently extracted lower third molars were collected. Scaling and polishing of teeth were done. Roots of teeth were embedded inside self cured acrylic resin blocks to form acrylic base with occlusal surfaces parallel to base of blocks. Crowns of teeth were sectioned at one third of the crowns to obtain a flat dentin surfaces. Total number of samples were divided into 3 groups each of one contained (10) samples as following : Group 1- dentin surfaces were treated with 35% phosphoric acid only. Group 2- dentin surfaces were treated with Er,Cr:YSGG laser only. Group 3- dentin surfaces were initially treated with Er,Cr:YSGG laser, then with 35% phosphoric acid. Bonding agent was applied to dentin surfaces and composite was applied by using rubber mold then light cured. Composite posts were released from molds then shear bond strength was measured. Statistical analysis showed that there was significant difference among all groups and acid etching group showed significant highest Shear bond strength followed by group of laser & acid etching then group of laser etching showed the significant least shear bond strength. From this study it can be concluded that etching of dentin with Er,Cr:YSGG laser can produce shear bond strength weaker than that of conventional acid etching.