Adhesive analysis of voids in class II composite resin restorations at the axial and gingival cavity walls restored under in vivo versus in vitro conditions

Composite resin may bond differently to dentin depending upon the amount of voids and the cavity wall involved. The bond to the gingival wall was not as reliable as the bond to the axial wall. An increase in the amount of surface voids was a major factor for reducing microtensile bond strengths of adhesive to dentin.