Effects of acid treatment of pulpal dentin before walking bleaching on the bond strength of composite resin restorations

Abstract

Prior acid treatment of the coronal pulp chamber dentin to remove the smear layer and open dentinal tubules is a promising approach for enhancing the effect of walking bleaching. This in vitro study was conducted to estimate how acid treatment with 40% phosphoric acid and 3% EDTA on the pulpal dentin before walking bleaching effects the bond strength of the subsequent composite resin restorations. Specimens that had received phosphoric acid treatment showed marked demineralization at the fractured dentin surface compared to specimens that had received EDTA treatment or the control which had received no treatment. These results showed that when the pulp cavity is treated with 40% phosphoric acid prior to walking bleaching, there is a risk that the demineralized dentin compromises the bond to the subsequent composite resin restoration. We concluded that phosphoric acid of less than 40% can be recommended to open the dentinal tubules before walking bleaching and yet maintain a strong bond of the subsequent resin composite restoration.