Effect of benzalkonium chloride applicationon resin-dentine bond strength

Abstract

BACKGROUND: Application of dentine adhesives to demineralized dentine, activates endogenous collagen-bound matrix metallopro-teinases principally (MMP) 2, 8 and 9, which results in progressive loss of collagen from hybrid layer. Recently, benzalkonium chloride (BAC) has been shown to be effective in inhibiting MMPs and it may be therefore useful in enhancing the stability of bonded restorations. AIM: To evaluate the effect of pretreatment of dentine with 0.5% BAC solution on bond strength of etch and rinse adhesives to dentine. DESIGN: Flat dentine surfaces prepared from 32 extracted caries-free third molars were etched with 37% phosphoric acid for 15s. The teeth were randomly assigned to one of the two groups (n = 16). In Group 1: acid-etched dentine surfaces were treated with 0.5% BAC solution and Group 2: did not have any pretreatment. Dentine surfaces were blotted dried, Single bond (3 M ESPE), or Prime & Bond NT (Dentsply De Trey) applied following the manufacturers’ instructions. Composite buildups (Z250, 3 M ESPE) were performed. After storage in water at 37°C for 24h, bonded teeth were cut into composite-dentine beams for microtensile bond strength testing. Data were analyzed by two-way ANOVA (pre-treatment and adhesives) and Tukey tests (α = 0.05). RESULTS: Pretreatment of dentine with BAC increased bond strength of adhesives to dentine (P < 0.001). Different adhesives had no significant effect on dentine bond strength (P > 0.05). CONCLUSION: Pretreatment of dentine with 0.5% BAC solution increased bond strength of etch-and-rinse adhesives to dentine. Future experiments will examine the effect of benzalkonium chloride on durability of resin-dentine bond.