Scanning Electron Microscope Study of Composite Restorative Materials

¹ Epoxylite Medical Research Center, Division of the Epoxylite Corporation, South El Monte, California 91733

The relatively new class of dental restoratives, termed composites, contain thermosetting resin binders and various concentrations of several different types of inert fillers. Because of the difference in types and amounts of resins and fillers present in these materials, each restorative has unique surface characteristics. In addition, the various resin types and filler loading volumes cause differences in polymerization shrinkage and adaptation to the margins of cavity preparations. A combination of radioisotope leakage studies and scanning electron microscopy studies was used to investigate the surfaces and adaptation of four of these composite materials in comparison to an amalgam, silicate, and unfilled poly(methyl methacrylate).