Using packable composites for direct posterior placement.

BACKGROUND: Although dentists have been using resin-based composites successfully to restore posterior teeth in Class II situations for several years, creating a functional, anatomical proximal contact remains a clinical challenge for many clinicians. OVERVIEW: This article presents a step by-step technique for creating a predictable proximal contact using a packable resin-based composite as the restorative material. Using a technique that is similar to that for amalgam will enable the dentist to make a successful transition to using composite as an alternative to amalgam in some posterior teeth. PRACTICE IMPLICATIONS: More patients today are well-informed about dental care and are seeking tooth-colored restorative alternatives. Excellent materials and proven techniques are making the transition from traditional metallic restorations easier and more predictable. With this article, the authors aim to help dentists gain confidence in their technique and enable them to provide this service for their patients.

Dentin adhesives for the twenty-first century.

The efforts of numerous clinical scientists have resulted in the development of tooth bonding systems that have changed the way clinical dentistry is practiced. The adhesion between polymeric restorative materials and dentin has been optimized to the point that little improvement can be expected within the next decade or even more. Already, the adhesion between the two substrates is greater than the inherent tensile strength of dentin itself. Improvements however, will undoubtedly occur in the manner in which the materials are used clinically. Such achievements are necessary to standardize performance as well as to eliminate postoperative sensitivity.

Porcelain esthetics for the 21st century.

BACKGROUND: Dental procedures play a vital role in the modern dental practice. Considerable research has addressed improvements in the properties of dental porcelains. CLINICAL IMPLICATIONS: This article examines the trends in the scientific advances in dental porcelains. It highlights properties of the new low-fusing porcelains and describes indications for their use. New luting cements also are addressed.

Properties and characteristics of an indirect Bis-GMA/barium-glass polymer ceramic restorative system.

Although porcelain has predictably served the dental profession for more than 200 years, this class of restorative material has presented a number of clinically undesirable characteristics. As a result, during the past several years, major efforts have been made to enhance the mechanical and physical characteristics of polymers to better mimic porcelain for specific clinical applications. In recent years, Bis-GMA/barium-glass polymer systems have been developed to offer dental professionals a versatile restorative alternative to porcelain. This article details the material properties and clinical characteristics of one such system for the esthetic restoration of anterior and posterior teeth.

Cavity wall adaptation of resin-based composites lined with flowable composites.

PURPOSE: To compare the adhesion of a flowable resin-based composite (RBC) vs. a condensable RBC to tooth structure using scanning electron microscopy (SEM). MATERIALS AND METHODS: Fifteen recently extracted human teeth were prepared for Class I restorations and equally divided into three groups. Group 1 was filled with Heliomolar bonded with Syntac Single Component. Group 2 was lined with Flow-It in addition to ALERT condensable RBC bonded with Bond-1 Primer/Adhesive. Group 3 was filled with ALERT bonded with Bond-1 Primer/Adhesive. All teeth were thermocycled, sectioned and evaluated for gap formation with the SEM. RESULTS: SEM at x15 demonstrated that restorations with the flowable RBC at the tooth/restoration interface showed no evidence of marginal gaps between the RBC material or at the underlying tooth structure. A significant difference (P < 0.05) in wall adaptation was found between Groups 2 and 3.

In vitro wear device for determining posterior composite wear.

BACKGROUND: An in vitro device has been developed to predict the long-term clinical performance of posterior composite resins. In contrast to most systems, it is based on three-bodied wear--the type of wear generated by food bolus during mastication. METHODS: The authors wear-tested two groups of materials that included posterior composite resins, a castable ceramic, an amalgam and an unsalinated composite resin. After the wear-testing device concluded 400,000 cycles, the authors evaluated replicas of restoration surfaces for material loss. They used scanning electron microscopy to determine the mechanism of wear. RESULTS: The authors detected considerable differences in wear among the various materials included in the study. All of the differences, however, fell within the range of results obtained from the positive and negative controls (unsilanated composite resin and ceramic, respectively). A comparison of the in vitro wear values with the wear values obtained from a series of ongoing clinical studies at the same institution revealed a high level of agreement. Furthermore, replicas of the laboratory-tested composite resin samples revealed the same wear patterns as those generated from clinical restorations. The variation coefficients for the in vitro data generally did not exceed 5 percent, whereas those for the clinical data commonly averaged 20 percent. CONCLUSIONS: Based on the results of this study, the authors conclude that the in vitro testing device is reliably capable of predicting long-term clinical wear values. The results obtained after 92 hours of wear testing correlated closely with those obtained after three years of clinical testing. CLINICAL IMPLICATIONS: Long-term clinical studies are both time-consuming and expensive. Reliable in vitro wear-testing techniques allow manufacturers to develop or modify composite resin systems in considerably shorter periods.