Effect of zinc-doping in physicochemical properties of dental adhesives

Abstract

Purpose: To evaluate changes in the physicochemical properties, water sorption (WS), solubility (SO), modulus of elasticity (E), ultimate tensile strength (UTS), and microhardness (MH) tests were undertaken in zinc-doped dental adhesives.

Methods: Two bonding resins, Adper Single Bond Plus (SB) and Clearfil SE Bond (SEB), were zincdoped by mixing them with 5, 10 or 20wt% of ZnO powder, or with 1 or 2wt% ZnCl2. Resin disks were made of each adhesive blend for the evaluation of WS, SO, and MH, and dumbbell-shaped specimens were prepared for E and UTS testing.

Results: An increase in WS and SO was observed for adhesives doped with ZnCl2. A reduction in WS was observed for the adhesive blends containing 10% or 20wt% ZnO, while the SO was not altered in any of the ZnO-doped adhesives. An increase in E values was observed only for the SB adhesive doped with ZnCl2. For SEB-blends, the incorporation of zinc compounds did not alter the E values. UTS values decreased when SEB was doped with ZnO. SBblends doped with 20wt% ZnO significantly increased their MH, and the addition of zinc to the SEB-blends augmented the MH values in all cases.