BACKGROUND Shrinkage occurs during polymerization of all resin composites, affecting not only the physical properties of the composites but also the marginal integrity of the restoration. Stepped photo-polymerization, in contrast to single-cure photo-polymerization, is said to minimize this shrinkage. The thickness of the increments of resin composite being cured may also be a factor in final s...

The purpose of this study was to quantify the cuspal deflection produced by polymerization shrinkage, comparing 3 different techniques in the placement and polymerization of Class II posterior composite resin restorations in vivo. Thirty primary second molars in need of a Class II restoration were identified. An index, with a size 1⁄4 carbide round bur, was placed on the buccal and lingual cusp...

Polymerization shrinkage of dental resin composites can lead to restoration debonding or cracked tooth tissues in composite-restored teeth. In order to understand where and how shrinkage strain and stress develop in such restored teeth, Digital Image Correlation (DIC) was used to provide a comprehensive view of the displacement and strain distributions within model restorations that had undergo...

Because of the dental profession's increased utilization of light-cured restorative materials, there has been a corresponding increase in research into the light sources used to initiate polymerization. The argon laser is one promising source, as the wavelength of light emitted by this laser is optimal for the initiation of polymerization of composite resins. The literature reflects a strong di...

The leading cause of oral pain and tooth loss is from caries and their treatment include restoration using amalgam, resin, porcelain and gold, endodontic therapy and extraction. Resin composite restorations have grown popular over the last half a century because it can take shades more similar to enamel. Here, we discuss the history and use of resin, comparison between amalgam and resin, clinic...

The purpose of this study was to compare the properties of 2 new dual-cure, bulk-fill restorative composite resins to those of a hybrid composite resin material. Depth of cure, fracture toughness, porosity, microleakage, and volumetric shrinkage properties were examined. With the exception of fracture toughness, significant differences were found among materials. Compared to the incrementally p...