Abstract
The aim of the present study was to evaluate the influence of retraction agents (Expasyl and viscostat) and bonding regimes [Total-etch, Self-etch and Er,Cr:YSGG (ECL) laser] on the shear bond strength (SBS) of resin composite to dentin. One hundred and eighty human mo-lars were prepared for exposure of occlusal dentin. Based on retraction agent treatments of dentin, teeth were equally divided into three main groups, A: Expasyl, B: Viscostat, C: No treatment (Control) (n=60). After dentin cleaning, dentin specimens in each group were bonded to resin composite (Tetric N-Ceram) using three different bonding regimes, 1: Etch & rinse, 2: ECL and 3: Self-etch. These combinations resulted in none study groups (n=20). Bonded specimens were exposed to shear bond strength testing using universal testing ma-chine under a standard load applied at crosshead speed of lmm/min. Failure mode of the fractured specimens were assessed using stereomicroscope. Data was analysed using analysis of variance and Tukey-Kramer multiple comparisons test.The maximum bond strength was displayed by group C1 (Etch & rinse + Tetric-N- Bond) (24.54 +/- 3.55 MPa) and lowest bond scores were in group B3 (Viscostat + Clearfill SE) (14.52 +/- 2.23 MPa). SBS was significantly higher in control s as compared to specimens exposed to Expasyl and viscostat in all corre-sponding groups (p<0.05). Different bonding techniques (Etch-rinse, ECI. and Self-etch) showed comparable SBS outcomes in all corresponding hemostatic agent groups (p>0.05). Most common failure mode among the specimens of study groups was adhesive. The use of haemostatic agents compromised bond integrity of resin composite to dentin irrespective of the bonding regime employed. Post haemostatic agent application, Er,Cr:YSGG, etch-rinse and self-etch conditioning techniques showed comparable bond strength outcomes of resin to dentin.