Influence of temperature on the visco-elastic properties of direct and indirect dental composite resins
Influence of temperature on the visco-elastic properties of direct and indirect dental composite resins
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DOI：
10.1016/j.dental.2007.06.025
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发表时间：
2008-05-01
期刊：
影响因子：
5
通讯作者：
Geis-Gerstorfer, Juergen
中科院分区：
文献类型：
--
作者：
Mesquita, Renata V.;Geis-Gerstorfer, Juergen
目标.本研究的第一个目的是确定两个直接（DiamondLite和Grandio）和两个间接（Artglass和Vita Zeta LC）牙科复合材料的粘弹性在很宽的温度范围内，以避免选择一个复合材料，将经历突然变化，其机械性能在service. Methods。在此目的内，在制造后立即测试复合材料或在37 ℃下在空气或蒸馏水中储存1天、7天或90天后测试复合材料。在动态测试期间，使用动态机械分析仪（DMA）在0至200摄氏度的温度范围内，在近似1 Hz的咀嚼频率下测定弹性模量（E“）、粘性模量（E”）和损耗角正切（tan δ）。基于它们的高玻璃化转变温度（T-g）以及材料在口腔中基本上在37 ° C下平衡并且不是热导体的事实，预计从37 ° C的温度变化很小，并且应该仅导致两种模量的适度变化。然而，当暴露于正常口腔温度和由于摄入热食物和饮料而导致的更高温度时，复合材料可能会提高其初始转化程度。这一事件可能对修复体产生积极和消极的影响，例如分别增加刚度和额外的微渗漏。根据这些结果，可以说，在模拟口腔环境的条件下监测牙科复合材料的粘弹性性能似乎是预测其作为修复材料的临床性能的有用工具。(c)2007年，牙科材料学院。由爱思唯尔有限公司出版。保留所有权利。
Objectives. The first aim of this study was to determine the visco-elastic properties of two direct (DiamondLite and Grandio) and two indirect (Artglass and Vita Zeta LC) dental composites over a wide range of temperatures, in order to avoid choosing a composite that would undergo sudden changes in its mechanical properties during service.Methods. Within this objective the composites were tested immediately after fabrication or after storage at 37 degrees C, either in air or distilled water for 1 day, 7 or 90 days. During dynamic testing, the elastic modulus (E'), viscous modulus (E '') and loss tangent (tan 6) were determined using a dynamic mechanical analyzer (DMA) over a temperature range from 0 to 200 degrees C, at an approximate masticatory frequency of 1 Hz.Results. Based on their high glass transition temperatures (T-g) and on the fact that materials are basically equilibrated at 37 degrees C in the mouth and are not thermal conductors, temperature changes from 37 degrees C are expected to be small and should lead to only modest changes in both moduli. However, composites might improve their initial degree of conversion when exposed to normal mouth temperature and higher temperatures due to the ingestion of hot food and beverages. This event can have positive and negative effects on the restoration, such as greater rigidity and additional micro-leakage, respectively.Significance. According to these results it could be said that monitoring the visco-elastic properties of dental composites under conditions that simulate the oral environment seems to be a useful tool to predict their clinical performance as restorative materials. (c) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.