Change of properties during storage of a UDMA/TEGDMA dental resin
Change of properties during storage of a UDMA/TEGDMA dental resin
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DOI：
10.1002/jbm.b.20022
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发表时间：
2004-02-15
影响因子：
3.4
通讯作者：
Sakaguchi, RL
中科院分区：
文献类型：
--
作者：
Lee, JK;Choi, JY;Sakaguchi, RL
本研究的目的是评估以udma为基础的牙科树脂在初始光照后的粘弹性随时间的变化。用可见光固化装置照射UDMA/TEGDMA （70:30 wt%）树脂标本。光固化后立即在37℃的黑暗中保存不同时间，从1到120 h，并通过DMA， DSC和FTIR光谱进行表征。辐照后的样品呈现出双峰形状，其形式是对数E′的两次快速下降，对应于玻璃化转变，在两次下降之间有一个平台。tan δ随温度变化有两个明显的峰。在辐照过程中，未完全固化的样品与被快速反应捕获的残余基团的热反应是导致高原的原因。贮藏后，动态力学参数、DSC放热和转化程度发生了显著变化。存储模量在4 h内继续增加，之后趋于平稳。tan δ峰高随温度的变化也受贮藏的影响。转化度从辐照后立即的75+/-2%增加到贮存120 h后的87+/-3%。这种牙科树脂系统在37度辐照后储存时的性能变化在临床上具有重要的稳定性，耐久性和初始聚合后的性能。(C) 2003 Wiley期刊有限公司
The aim of this study was to evaluate the changes in viscoelastic properties of a UDMA-based dental resin as a function of time after initial light exposure. Specimens of a UDMA/TEGDMA (70:30 wt%) resin were irradiated by a visible-light-curing unit. Immediately after the irradiation, the light-cured specimen was stored in the dark for different times from 1 to 120 h at 37 degreesC, and characterized by means of DMA, DSC, and FTIR spectroscopy. The irradiated specimen exhibited a bimodal shape in the form of two rapid declines in log E' corresponding to glass transition with a plateau between the two declines. Two distinct peaks were seen in tan delta versus temperature. The thermal reaction of the incompletely cured sample with residual groups trapped by the fast reaction during irradiation is responsible for the plateau. After storage, significant changes were observed in dynamic mechanical parameters, DSC exotherm, and degree of conversion. Storage modulus continued to increase during the 4 h of storage and leveled off thereafter. Peak heights of tan delta versus temperature were also influenced by storage. Degree of conversion increased from 75+/-2% immediately after irradiation to 87+/-3% after 120 h storage. The changes of the properties of this dental resin system when stored at 37 degreesC after irradiation are clinically important in terms of stability, durability, and performance after initial polymerization. (C) 2003 Wiley Periodicals, Inc.