Effects of acid etchants on dentin

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.

An adhesie dental restorative material

Development of elastomeric polyurethane resins for use as adhesive liners under composite restorative materials is reviewed. The elastic nature of these adhesive films appears to provide a marginal seal despite dimensional changes of the restorative material. Adhesive strengths of 1,500 psi to enamel have been maintained after thermal cycling and after storage for one year in water.

Sealing of developmental pits and fissures. I. In vitro study

Development and laboratory evaluation of a thermosetting polyurethane resin designed for use as a pit and fissure sealant was conducted. The material exhibited adhesion to enamel in excess of 1,300 psi. Radioautographs and scanning electron photomicrographs did not indicate leakage of isotope and showed an intimate contact between the resin and the fissure walls. The resin appeared to penetrate into the deepest fissures. The material is hydrolysis resistant; 90% of the original adhesive strength was retained after one year in 37 C water.

Scanning electron microscope study of composite restorative materials

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).

Physical properties of four thermosetting dental restorative resins

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.