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Type: Artigo de periódico
Title: Can phenyl-propanedione influence Knoop hardness, rate of polymerization and bond strength of resin composite restorations?
Author: Brandt, WC
Tomaselli, LD
Correr-Sobrinho, L
Sinhoreti, MAC
Abstract: Objectives: The aim of this study was to evaluate the degree of conversion (DC), rate of polymerization (R(p)(max)), Knoop hardness (KHN) and bond strength between tooth/restoration of composite resins containing different photo-initiators photo-activated by different light-curing units (LCUs). Materials and methods: A mixture of BisGMA, UDMA, BisEMA and TEGDMA was prepared along with the following photo-initiators: camphorquinone (CQ), phenyl-propanedione (PPD) or the association (CQ/PPD) and 65 wt% of silanated filler particles. The LCUs included a halogen lamp XL 2500 and two LEDs: UltraBlueIS and UltraLume5. The conversion profiles during photo-polymerization were investigated using middle-infrared spectroscopy (mid-IR). Bond strength was evaluated using push-out test in ninety teeth with prepared cavities. Before the push-out test, Knoop hardness (KH) was verified in the top and at the base of the restorations. Results: PPD obtained lower R(p)(max) values, regardless of the LCU used. It also provided a greater bond strength than CQ when the LEDs LCUs were used. The degree of conversion after 40 s of irradiation was the same for all composite resins, except PPD photo-activated for XL 2500, which showed lower DC values than CQ and CQ/PPD. In the top and at the base of the restorations, PPD showed the lowest KH values when photo-activated with XL 2500. XL 2500 produced higher KH values than UltraBlueIS when used with CQ or CQ/PPD photo-initiators. Conclusion: Because it increased the bond strength without compromising the properties of composite resins when photo-activated by an LED, PPD can be used as an alternative photo-initiator. (C) 2011 Elsevier Ltd. All rights reserved.
Subject: Photo-initiator
Dental resins and composites
Bond strength
Country: Inglaterra
Editor: Elsevier Sci Ltd
Citation: Journal Of Dentistry. Elsevier Sci Ltd, v. 39, n. 6, n. 438, n. 447, 2011.
Rights: fechado
Identifier DOI: 10.1016/j.jdent.2011.03.009
Date Issue: 2011
Appears in Collections:Unicamp - Artigos e Outros Documentos

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