Objectives:The purpose of this study was to determine color changes and surface roughness of composites when they were subjected to in-office bleaching.Methods:12 discs 15 mm in diameter and 2 mm thick were prepared from two shades (A2 & A4) of two composites, Durafil VS (DF) and TPH3 (TPH). Specimens were polished and stored in distilled water for 24 hours at 37°C before being subjected to bleaching, staining, and re-bleaching. Each of the groups of specimens (DF-A2, DF-A4, TPH-A2 and TPH-A4) were subdivided into three subgroups (n=4) and bleached with Beyond, LumaWhite-Plus, and Opalescence-Boost. Specimens were then stained by immersing them in a coffee solution for 48 hours at 37°C, and then they were re-bleached. Colorimetric measurements were performed at baseline, after bleaching, after staining, and after re-bleaching. Surface roughness was determined with environmental SEM before and after bleaching. Data were statistically-analyzed.Results:None of the bleaching systems notably changed the color of composites (delta-E<2). Coffee staining affected DF specimens more than TPH. Stained specimens showed variable responses to whitening with no significant color change observed with TPH (delta-E<2) and significant changes observed with DF. Surface roughness significantly changed with bleaching, but the degree varied according to composite shade and bleaching agent.Conclusions:Three in-office bleaching agents had no significant color changes on two composites. DF showed more color change than TPH when immersed in coffee. Stained composites showed different degrees of whitening, with DF showing more response. Bleaching may adversely affect the surface texture of composites. Dentists should take into consideration that composite restorations may not respond to bleaching in the same way that natural teeth do.

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Fiber inserts incorporated at the gingival floor of Class II composite restorations resulted in a significant reduction of microleakage scores as compared to restorations made without inserts. This may lead to a reduced incidence of recurrent caries. SUMMARYPurpose: This investigation evaluated the effect of glass and polyethylene fiber inserts on the microleakage of Class II composite restorations with gingival margins on root surfaces. Methods: Fifty-four intact molars were sterilized with Gamma irradiation and mounted in acrylic bases. Class II slot cavities were made on both proximal sides of each tooth (3 mm wide, 1.5 mm deep) with the gingival margin on the root surface. The teeth were divided into nine groups, according to the technique of restoration and type of bonding agent. Filtek P-60 (3M/ESPE) was used to restore all cavities. Two types of fiber inserts were used: glass fiber (Ever Stick, StickTech) and polyethylene (Ribbond-THM), with three bonding agents being employed: Scotch Bond Multipurpose (3M/ESPE), Clearfil SE Bond (Kuraray) and Xeno IV (Dentsply). In the experimental groups, 3 mm long fiber inserts were inserted into restorations at the gingival seat. The control groups had no fiber inserts. The restorations were made incrementally and cured with LED light (UltraLume5, Ultradent). The restored teeth were stored in water for two weeks, then thermocycled for 3,000 cycles (5°C and 55°C). The tooth surfaces were sealed with nail polish, except at the restoration margins. The teeth were immersed in 2% procion red dye solution, sectioned and dye penetration was assessed to determine the extent of microleakage

The use of separation rings with sectional matrices provides superior contacts when placing Class II RCRs.

A high-intensity LED LCU used for 10 seconds resulted in RH values greater than 80%, with all four restoratives tested indicating a sufficient degree of monomer conversion with such a short curing cycle.

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SUMMARY Objective The objective of this study was to investigate, by simulation, the effect of conventional composite resin insertion techniques on cuspal deflection using bonded typodont artificial teeth. The deflection produced by a new low-shrinkage composite was also determined. Materials and Methods Sixty standardized MOD preparations on ivorine maxillary premolars were prepared: group A at 4 mm depth and group B at 6 mm depth. Each group was further subdivided according to composite insertion technique (n=6), as follows: 1) bulk insertion, 2) horizontal increments, 3) tangential increments, and 4) a modified tangential technique. Preparations were microetched, acid-cleaned, and bonded with adhesive resin to provide micromechanical attachment before restoration with a conventional composite (Spectrum TPH3, Dentsply). Two additional subgroups at 4 mm and 6 mm depth (n=6) were restored in bulk using low-shrinkage composite (Filtek LS, 3M/ESPE). All groups received the same total photo-polymerization time. Cuspal deflection was measured during the restorative procedure using two Linear Variable Differential Transformers attached to a data acquisition system. Results The average cuspal deflections for group A were 1) 40.17 ± 1.18 μm, 2) 25.80 ± 4.98 μm, 3) 28.27 ± 5.12 μm, and 4) 27.33 ± 2.42 μm. The deflections in group B were 1) 38.82 ± 3.64 μm, 2) 50.39 ± 9.17 μm, 3) 55.62 ± 8.16 μm, and 4) 49.61 ± 8.01 μm. Cuspal flexure for the low-shrinkage composite was 11.14 ± 1.67 μm (group A: 4 mm depth) and 16.53 ± 2.79 μm (group B: 6 mm depth). Conclusions All insertion techniques using conventional composite caused cuspal deformation. In general, deeper preparations showed increased cuspal deflection—except in the case of bulk insertion, which was likely affected by decreased depth of cure. Cuspal movement using low-shrinkage composite was significantly reduced.