Effects of a barbituric acid/CuCl2 initiator system on resin adhesion to dentin

The effectiveness of a barbituric acid/copper (II) chloride initiator system in dentin was examined in terms of the effects of barbituric acid structures and dentin conditioners on bond strength. Curing times and tensile bond strengths to bovine dentin were measured for PMMA/MMA resins in conjunction with initiators consisting of a combination of CuCl2 and four barbituric acids having different substituents. The dentin surfaces were treated with six conditioners consisting of 10% citric acid or phosphoric acid with or without 3% FeCl3 and CuCl2. Among the four barbituric acid systems studied, curing times varied significantly (p < 0.002), but the bond strengths to dentin, conditioned with 10% citric acid containing 3% CuCl2, did not (p > 0.60). The dentin conditioners influenced bond strength significantly (p < 0.02). The phosphoric acid based conditioners produced higher bond strengths than those based on citric acid. The bond strengths obtained under optimal conditions were comparable to those reported for MMA-TBB resin. Thus, the resin applied using the barbituric acid/CuCl2 system worked as well as one of the most effective bonding resins available.