Bond strength of fiber-reinforced posts to deproteinized root canal dentin

Abstract

Aim: This study evaluated the push-out bond strength of cementedfiber posts after deproteinization of root canal dentin wallswith NaOCl. The effect of the application of an antioxidant solution(sodium ascorbate) was also evaluated.Materials and methods: A three-step etch-and-rinse (Scotchbond- 3M Espe) and a one-step self-etching adhesive (XenoIII - Dentsply Caulk) were evaluated. Thirty bovine incisor rootswere divided into 3 groups:a. Irrigation with physiologic solution (control).b. Deproteinization with 10 minutes irrigation of 5% NaOCl.c. Deproteinization with NaOCl followed by 10 minutes irrigationwith 10% ascorbic acid. Fiber posts were cementedwith a dual-cured cement (Rely X ARC - 3M ESPE).The push-out bond strength was evaluated after24 hours of storage in distilled water. The data were analyzedwith three-way ANOVA, one-way ANOVA and Tukey'stest (α = 0.05). Results: There were significant differences between groups(p < 0.05). The bond strength of Scotchbond was not influencedby the deproteinization. Xeno III showed a decrease in bondstrength when deproteinized with 5% NaOCl (p < 0.05). ForXeno III, the subsequent irrigation with ascorbic acid was ableto reverse the effect of the deproteinization. Considering theradicular thirds, the bond strength varied in the sequence-apical< middle < coronal.Conclusion: Only the all-in-one adhesive was influenced bythe deproteinization. Considering the respective control groups,both systems showed similar bond strength results.Clinical significance: The decreased bond strength of the selfetchingadhesive following deproteinization seams to be relatedto the oxidant effect of the NaOCl solution and the subsequentirrigation with ascorbic acid was able to reverse the effect ofthe deproteinization.