No abstract

A Faria-e-Silva L Boaro R Braga E Piva V Arias L Martins Clinical RelevanceUnder clinical conditions, delayed light activation of dual-cured resin cements may be advantageous in order to reduce shrinkage stress. SUMMARYObjectives: This study evaluated the effect of light activation (absence, immediate, or delayed) on conversion kinetics and polymerization stress of three commercial dual-cured resin cements (Enforce, RelyX ARC, and Panavia F). Methods: Degree of conversion (DC) was monitored for 30 minutes using real-time nearFourier transform infrared spectroscopy. The cement was mixed, placed on the spectrometer sample holder, and light activated either immediately or after five minutes (delayed light activation). When no light activation was performed, the materials were protected from light exposure (control). DC was evaluated at five and 30 minutes postmixture. Maximum rates of polymerization (Rp max ) were obtained from the first derivative of the DC vs time curve. Polymerization stress was monitored for 30 minutes in 1-mm-thick specimens inserted between two cylinders attached to a uni-

©Operative Dentistry, 2010, 35-5, 515-521 AL Faria-e-Silva • MM Fabião VG Arias • LRM Martins Clinical RelevanceThe light activation of dual-cured resin cements is essential for improved shear bond strength. Bond strength is low in the first minutes following insertion of a resin cement and increases over time. Under clinical conditions, care should be taken to limit occlusal stress immediately after luting an indirect restoration. SUMMARY

Seafood mislabeling is a problem worldwide because it may cause underreporting of species exploitation and have detrimental effects on endangered species conservation. The persistence of this problem has been documented for important commercial species, revealing the need to devote more effort to provide effective management and control measures. In this study, we have applied DNA authentication tools, sequences of two mitochondrial genes, for authentication of 245 samples of fish marketed in Spain, one of the top fish consumer countries in the world. Fresh, frozen, smoked, salted, and cooked products were analyzed. Successful DNA extraction and positive polymerase chain reaction (PCR) amplification were obtained for all products. DNA sequences revealed greater than 7% mislabeling, unequally distributed among products, fish groups, and supply points where samples were obtained. Significantly higher mislabeling was found for unrecognizable processed products than for whole fish, suggesting that mislabeling is likely deliberate. Lower mislabeling occurred in samples purchased from local grocery stores in comparison with bigger supermarkets, wholesalers, and restaurants. In the case of anglerfish, underreported exploitation of the species from the Pacific Ocean is likely. The results emphasize the need for controlling the labels in different points of the fish supply chain and authenticating species, particularly in processed seafood.

The purpose of this in vitro study was to evaluate the efficacy of three hydrophilic dentin adhesive systems to reduce class II restoration microleakage. A total of 60 human molar teeth were used in which two box cavities were made on the distal and mesial surfaces, with a cervical margin in dentin. These cavities were randomly divided into 3 groups (n = 40 each), according to adhesive system tested: G1: OptiBond SOLO; G2: Amalgambond Plus; G3: Etch & Prime 3.0. The cavities were restored with the composite resin Z-100. The groups were thermocycled 2000 times (5 +/- 1 degrees C and 55 +/- 1 degrees C) with a dwell time of 1 min. The teeth were then immersed in 2% methylene blue, pH 7.0, for 4 h, sectioned and observed with a stereomicroscope MEIJI 2000 (35X). The evaluation was made using scores (0-4) and the results were expressed through the sum of the ranks. G1 = 1994.00; G2 = 2294.00; G3 = 2972.00. The three groups were significantly different. The self-etching adhesive system Etch & Prime 3.0 was less effective in preventing microleakage. The OptiBond SOLO adhesive was the most effective in reducing microleakage in dentin margins when compared with Amalgambond Plus and Etch & Prime 3.0.