Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/759
Type: Artigo de periódico
Title: BisGMA/TEGDMA ratio and filler content effects on shrinkage stress
Author: GONCALVES, Flavia
AZEVEDO, Caio L. N.
FERRACANE, Jack L.
BRAGA, Roberto R.
Abstract: Objective. To investigate the contributions of BisGMA:TEGDMA and filler content on polymerization stress, along with the influence of variables associated with stress development, namely, degree of conversion, reaction rate, shrinkage, elastic modulus and loss tangent for a series of experimental dental composites. Methods. Twenty formulations with BisGMA: TEGDMA ratios of 3: 7, 4: 6, 5: 5, 6: 4 and 7: 3 and barium glass filler levels of 40, 50, 60 or 70 wt% were studied. Polymerization stress was determined in a tensilometer, inserting the composite between acrylic rods fixed to clamps of a universal test machine and dividing the maximum load recorded by the rods cross-sectional area. Conversion and reaction rate were determined by infra-red spectroscopy. Shrinkage was measured by mercury dilatometer. Modulus was obtained by three-point bending. Loss tangent was determined by dynamic nanoindentation. Regression analyses were performed to estimate the effect of organic and inorganic contents on each studied variable, while a stepwise forward regression identified significant variables for polymerization stress. Results. All variables showed dependence on inorganic concentration and monomeric content. The resin matrix showed a stronger influence on polymerization stress, conversion and reaction rate, whereas filler fraction showed a stronger influence on shrinkage, modulus and loss tangent. Shrinkage and conversion were significantly related to polymerization stress. Significance. Both the inorganic filler concentration and monomeric content affect polymerization stress, but the stronger influence of the resin matrix suggests that it may be possible to reduce stress by modifying resin composition without sacrificing filler content. The main challenge is to develop formulations with low shrinkage without sacrificing degree of conversion. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
Subject: Resin composites
Organic matrix
Inorganic content
Polymerization stress
Mechanical properties
Country: Inglaterra
Editor: ELSEVIER SCI LTD
Citation: DENTAL MATERIALS, v.27, n.6, p.520-526, 2011
Rights: fechado
Identifier DOI: 10.1016/j.dental.2011.01.007
Address: http://apps.isiknowledge.com/InboundService.do?Func=Frame&product=WOS&action=retrieve&SrcApp=EndNote&UT=000290021400004&Init=Yes&SrcAuth=ResearchSoft&mode=FullRecord
http://dx.doi.org/10.1016/j.dental.2011.01.007
Date Issue: 2011
Appears in Collections:IMECC - Artigos e Outros Documentos

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