The ability of acid etchants to penetrate dentin was tested under simulated clinical conditions. No penetration of the dentinal tubules by acid was detected by use of two different test methods, although pronounced roughening of the treated surfaces was observed.

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).

No abstract

A method for accelerated testing of dental composite restorative materials is described, and results of these tests are reported. The uniform testing showed considerable variation in the properties of the eight materials included in the study.

Four aromatic, thermosetting, composite dental restorative materials were evaluated for their mechanical and physical properties. The properties of two materials approached those of dentin and dental amalgams. One of the materials tested appeared to have the necessary requirements for use as both an anterior and posterior restorative material.