Faculty Bibliography

Composites are widely used for the functional and esthetic restorations of anterior teeth. The placement of a cavosurface margin bevel on the enamel margins of anterior composite preparations traditionally has been recommended to enhance retention and for esthetic reasons, as bevels result in a gradual transition between the restoration and the tooth. However, advances in adhesive and composite technology, as well as careful composite selection and application techniques, have made it possible to place adequate anterior composites without a bevel. Elimination of bevels results in more conservative cavity preparations, a simpler technique, a reduced restored surface area, and the preservation of tooth structure when the restoration is replaced. This Critical Appraisal summarizes clinical reviews and laboratory publications related to the influence of cavity preparation and, more specifically, cavosurface bevels on the performance of anterior composite restorations.

PURPOSE/OBJECTIVE:Repair of worn, broken or discolored composite restorations can be accomplished using new composite material and dentin bonding systems. The purpose of this study was to investigate the effectiveness of self-etching adhesive systems for composite re-bonding procedures onto different composite substrates that had been aged for 6 years prior to testing. MATERIALS AND METHODS/METHODS:Two hundred cylinders (4 mm x 5 mm) of composite were fabricated using 4 hybrid composites [AeliteFil (Bisco), Prodigy (SDS Kerr), TPH (Dentsply Caulk), and Z100 (3M ESPE)] following manufacturers' directions and stored for 6 years in 1% NaCl solution. After aging, each specimen was wet polished through 600-grit SiC and randomly assigned to a self-etching bonding system (Adper Prompt L-Pop/Z100 [3M ESPE]; Tyrian One-Step Plus/AeliteFil [Bisco]; OptiBond Solo Plus SE/Prodigy [SDS Kerr], Xeno III/TPH [Dentsply Caulk]) or a total-etch control (Prime&Bond NT/TPH [Dentsply Caulk]) (n = 10 per group). Shear bond strengths (SBS) for repairs were evaluated after 48 h (crosshead speed = 0.5 mm/min) and were compared by two-way ANOVA (p = 0.05) with Tukey post-hoc tests. RESULTS:Significant differences (p < or = 0.05) were detected for the main effects (substrates and bonding systems), but the interaction was not significant. SBS for bonding systems were from highest to lowest: (1) Prime&Bond NT, (2) OptiBond Solo Plus SE, (3) Adper Prompt L-Pop, (4) Xeno III, (5) Tyrian One-Step Plus. SBS of the repair systems to Z100 were significantly lower than those to the other composite substrates. CONCLUSION/CONCLUSIONS:Self-etching systems can be used to repair aged composite, but the efficacy of repair of aged composite is system dependent.

BACKGROUND:There exists limited data in the literature regarding the efficacy and safety of consumer-available, paint-on bleaching solutions. PURPOSE/OBJECTIVE:The purpose of this in vitro study was to evaluate the effect of two consumer-available, paint-on bleaching products on enamel microhardness against a control and a dentist-prescribed, home-applied (DPHA) bleaching product. MATERIALS AND METHODS/METHODS:Eighty enamel slabs were obtained from extracted human teeth and randomly divided into four treatment groups: (1) control; (2) Opalescence (Ultradent Products, Inc., South Jordan, UT, USA); (3) Crest Night Effects (Procter & Gamble, Cincinnati, OH, USA); and (4) Colgate Simply White Night (Colgate-Palmolive Co., Piscataway, NJ, USA). Opalescence is a carbamide peroxide DPHA product, whereas Crest Night Effects and Colgate Simply White Night are consumer-available products. The specimens in groups 2 to 4 underwent 2 weeks of treatment for 8 h/d. Specimens were maintained in artificial saliva at 37 degrees C between treatments. Subsequently, one-half of the specimens in groups 2 to 4 (n=10) underwent an additional seven treatments for 8 h/d, while the other half were stored in artificial saliva, receiving no further treatment. Microhardness was measured as Knoop hardness numbers (KHNs) at baseline and after 1, 7, 14, and 21 treatment days. The results were analyzed for statistical significance both intra- and intergroups using analysis of variance (p=.05). RESULTS:A statistically significant reduction in mean KHN was observed compared with baseline at 1, 7, 14, and 21 treatment days for group 4 and at 7 treatment days for group 3. When compared with the control or DPHA product, group 4 was the only treatment that resulted in significantly lower mean KHNs at 7, 14, and 21 treatment days. CONCLUSION/CONCLUSIONS:When evaluating enamel microhardness, consumer available, paint-on bleaching solutions may adversely affect enamel microhardness compared to a control and 10% carbamide peroxide DPHA bleaching solution. CLINICAL SIGNIFICANCE/CONCLUSIONS:With numerous consumer-available bleaching products on the market, it is crucial to be judicious in their selection and use. The results of this in vitro study showed that the consumer-available, paint-on bleaching solutions adversely affected enamel microhardness at some time during the study. Consumers should be made aware of this effect on enamel.