Effect of Dimethyl Sulfoxide Pretreatment on Dentin Wettability and Resin-Dentin Bond Strength; an in vitro study

Abstract

This study aimed to investigate the effect of dimethyl sulfoxide wet bonding technique, using three different concentrations, in enhancing the dentin wettability by the adhesive and the resin-dentin bond strength durability. DMSO wet bonding technique was compared to ethanol wet bonding technique in its simplified form and the conventional bonding technique. The two adhesive resins used were, single bond 2 (SB2), a two-step etch and rinse adhesive and single bond universal (SU) which was applied in etch and rinse mode. Two adhesive resins were investigated to clarify which adhesive best matches the pretreatments used providing higher resin-dentin bond durability. Specimens were randomly distributed into five groups according to the pretreatment used; each group was further divided into 2 subgroups according to the adhesive applied. Dentin specimens that remained untreated served as the control group. The wettability of the adhesive by DMSO vs. ethanol saturated dentin was evaluated through contact angle measurement. Teeth were cut parallel to the occlusal surface to obtain flat dentin slices. A total of 50 slices were obtained, each one measuring 1mm (±1mm) in thickness and checked using a digital caliper. Following the acid etching procedure, dentin pretreatments using (DMSO: 0.004%, 5%, and 50% or ethanol 100%) were applied using a saturated micro-brush and left for 1 min. A micro-pipette (Topette Pipettor, Dragon lab) was adjusted to dispense a 10µl droplet of either SB2 or SU adhesive on the flat dentin surface. For the control group, the adhesive was applied on the dentin slices immediately. A digital microscope (Dino-Lite microscope, India) was used for the measurement of the adhesive contact angles.