Surface failure of commercial and experimental restorative resins.

A single-pass test was used to study the surface failure of commercial and experimental restorative resins and composites. The surface failure observed for unfilled diacrylate resins was more severe than that seen for an unfilled acrylic resin. Addition of nonsilanated filler to the diacrylate resins increased the resistance to penetration but did not dramatically change the mode of surface failure. The surface failure of the commercial composite resins, which contain silanated filler, was ductile in mode and the resistance to penetration of the diamond slider was the highest of the materials studied. The wear of restorative resins and composites is determined, therefore, by resistance to penetration as well as mode of deformation during sliding.