Influence of thermal expansion on shrinkage during photopolymerization of dental resins based on bis-GMA/TEGDMA
Influence of thermal expansion on shrinkage during photopolymerization of dental resins based on bis-GMA/TEGDMA
复制标题
DOI：
10.1016/j.dental.2008.04.014
复制
发表时间：
2009-01-01
期刊：
影响因子：
5
通讯作者：
Vallo, Claudia
中科院分区：
文献类型：
--
作者：
Mucci, Veronica;Arenas, Gustauo;Vallo, Claudia
Objective.本研究的目的是评估基于bis-GMA-TEGDMA的未填充牙科树脂在光聚合过程中发生的体积变化。通过添加蒽醌（CQ）与甲基丙烯酸二甲氨基乙酯（DMAEMA）或4-二甲氨基苯甲酸乙酯（EDMAB）的组合，树脂被活化用于可见光聚合。采用基于Fizeau型干涉仪的光纤传感方法监测光聚合过程中的收缩。对直径为10 mm的不同厚度（1 mm和2 mm）的试样进行测量。聚合的高放热性质导致在加热期间的体积膨胀，并且当样品厚度增加时，这种效果更加明显。两种方法来评估由于热效应的体积变化。由于橡胶状树脂和玻璃状树脂之间的热膨胀系数的差异，由于热膨胀引起的体积增加大于由于热收缩引起的体积减小。结果，玻璃化树脂的体积大于由聚合收缩计算的体积。观察到的收缩率与样品厚度的趋势解释在整个光聚合过程中的光衰减的路径长度。在这项研究中获得的结果突出了非等温光聚合和体积变化在本体聚合系统的内在联系。(C)2008年，牙科材料学院。由爱思唯尔有限公司出版。保留所有权利。
Objective. The aim of this study was to assess volume changes that occur during photopolymerization of unfilled dental resins based on bis-GMA-TEGDMA.Methods. The resins were activated for visible light polymerization by the addition of camphorquinone (CQ) in combination with dimethylamino ethylmethacrylate (DMAEMA) or ethyl-4-dimethyl aminobenzoate (EDMAB). A fibre-optic sensing method based on a Fizeau-type interferometric scheme was employed for monitoring contraction during photopolymerization. Measurements were carried out on 10 mm diameter specimens of different thicknesses (1 and 2 mm).Results. The high exothermic nature of the polymerization resulted in volume expansion during the heating, and this effect was more pronounced when the sample thickness increased. Two approaches to assess volume changes due to thermal effects are presented. Due to the difference in thermal expansion coefficients between the rubbery and glassy resins, the increase of volume due to thermal expansion was greater than the decrease in volume due to thermal contraction. As a result, the volume of the vitrified resins was greater than that calculated from polymerization contraction. The observed trends of shrinkage versus sample thickness are explained in terms of light attenuation across the path length during photopolymerization.Significance. Results obtained in this research highlight the inherent interlinking of nonisothermal photopolymerization and volumetric changes in bulk polymerizing systems. (C) 2008 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.