Effect of Dentin Deproteinization Using Sodium Hypochlorite and Bromelain Enzyme on Microtensile Bond Strength of Self-etch Adhesives at Different Dentin Depths: An in-Vitro Study

Abstract

Background: Dentin bonding is challenging due to structural differences between superficial and deep dentin. The study aimed to evaluate the effect of dentin deproteinization using sodium hypochlorite (NaOCl) and bromelain enzyme on the microtensile bond strength (µTBS) of self-etch adhesive to superficial and deep dentin.
Materials and Methods: Forty-eight sound human third molars were randomly assigned into two main groups according to dentin depth. Each group was further subdivided into three subgroups (n=8) according to surface treatment: control (no pretreatment), 10% NaOCl, and 10% bromelain enzyme. After adhesive application and resin composite buildup, specimens were thermocycled then sectioned into beams to be subjected to µTBS testing.
Results: In superficial dentin, the control group showed significantly higher µTBS values compared with NaOCl and bromelain, with no significant difference between the two deproteinizing agents. In deep dentin, both NaOCl and bromelain significantly improved µTBS compared with control with NaOCl showed higher mean values compared to bromelain. Conclusions: Deproteinization with sodium hypochlorite or bromelain enhances bonding to deep dentin but decreased bonding to superficial dentin