Effects of dentin conditioning with NaOCl on shear bond strength of adhesive systems

Objective To evaluate the influence of sodium hypochlorite(NaOCl) deproteinization on shear bond strength of resin bonded to dentin. Methods Sixty recently extracted human molars free from caries were split longitudinally to expose the fresh dentin surface.After polishing with 600-grid SiC sandpaper,the teeth were randomly assigned to 5 groups and received the following treatment: ①phosphoric acid,15s;②(10%) NaOCl,120s;③phosphoric acid,15s,followed by(10%) NaOCl,60s;④(10%) NaOCl,120s,followed by phosphoric acid,15s;⑤distilled water treatment and served as control.Composite resin was bonded to the dentin surface by One-Step(OS),PrimeBond NT(PB) or Single Bond(SB),respectively.The specimens were stored in distilled water for 24 hours at(37℃).Shear bond strength test was performed;the data were statistical analyzed by ANOVA. Results There was no statistical difference among adhesives when phosphoric acid conditioning was performed.The bond strength of OS was significantly increased after dentin treated by NaOCl following acid etching(P(0.05)).Application of NaOCl alone significantly increased the bond strength of PB(P(0.05)). Conclusion NaOCl is a promising dentin conditioner;extensive evaluation of the bond properties of it should be performed.