influence of antioxidants on the morphological and mechanical characteristics of resin bonded dentin interface after bleaching

ABSTRACT

Anstract The purpose of this study was twofold, first to evaluate the effect of 50% hydrogen peroxide bleaching agents on surface morphology, ultra-structure of resin-dentin interface and the shear bond strength of resin composite to dentin. Second, to evaluate the effect of application of two different forms of antioxidants on the bleached dentin surface on the fore mentioned properties. One adhesive system [Dentastic Uno]. Epic TMPT microfilled composite. 50% bleaching gel and two antioxidants namely sodium ascorbate and vitamin C were used in this study. 56 intact maxillary first premolars were used. The teeth were equally divided into four groups, fourteen specimens each. Group I was directly bonded with composite resin without bleaching, group II was subjected to bleaching prior to composite bonding, whereas group III and IV were treated with sodium ascorbate and vitamin C antioxidants respectively after bleaching then bonded with resin composite. The teeth were examined by SEM to investigate dentin surface topography and resin- dentin interface. All samples were also subjected to shear bond strength testing using a universal testing machine