Effects of pretreating preparations with sodium hypochlorite on bonding composite resin restorations

This study sought to determine whether using sodium hypochlorite (NaOCl) as a pretreatment in bonding composite resins has a detrimental effect on bond strength. Previous studies have addressed pretreating dentin with NaOCl after etching; however, little research is available concerning pretreatment before etching. This study examines pretreating dentin with NaOCl prior to acid etching when fourth generation bonding systems are used. Thirty noncarious teeth were selected and sectioned horizontally at the occlusal third of the clinical crown. The teeth were divided into 3 groups (n = 10). Group 1 was the control group, with composite resin bonded to the dentin surface per manufacturer's instructions. Group 2 was pretreated with 6% NaOCl for 10 seconds; then, composite resin was bonded to the dentin as in Group 1. Group 3 was pretreated with 6% NaOCl for 20 seconds; then composite resin was bonded to the dentin as in Group 1. The specimens were stored in water for 24 hours, then thermocycled for 1000 cycles at temperatures of 5°C and 60°C. The specimens were shear tested until failure. According to the 1-way ANOVA testing (α = 0.05), using NaOCl as a pretreatment prior to etching with a specific fourth generation bonding agent does not affect bond strength.