Evaluation of resin composite polymerization by three dimensional micro-CT imaging and nanoindentation
Evaluation of resin composite polymerization by three dimensional micro-CT imaging and nanoindentation
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DOI：
10.1016/j.dental.2011.07.008
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发表时间：
2011-11-01
期刊：
影响因子：
5
通讯作者：
Tagami, Junji
中科院分区：
文献类型：
--
作者：
Cho, Eitetsu;Sadr, Alireza;Tagami, Junji
目标.光固化复合材料在聚合期间经历收缩。本研究的目的是评估区域内的光固化复合材料在聚合过程中的收缩，通过微计算机断层扫描和纳米压痕在粘结或非粘结类I cavity. Methods的机械性能。将氧化锆球形填料（直径30 μ m）作为标记物加入到复合树脂中，用或不用粘合剂填充到盒形I类空腔中。使用软件（TRI/3D-BON）在聚合之前和之后通过微CT获得的3D扫描中追踪标记填料。在每250 μ m深度处通过纳米压痕测定的树脂复合材料的平均硬度对深度作图。在粘结型腔中，顶部区域的填料颗粒向型腔底部移动，但在更深的深度，垂直移动的方向改变为向型腔顶部（辐照表面）。填充物位移与复合深度之间存在显著的线性回归关系（R（2）= 0.9761）。在无界腔中，所有的填料都向光固化源移动，并且填料位移与复合材料深度之间存在显著的幂律回归关系（R（2）= 0.849）。在这两组中，数据分散在深度超过3.5 mm的区域增加，其中代表复合材料转化程度的硬度与表面区域相比显著降低。区域聚合收缩的大小和方向取决于边界条件、深度和转化程度。聚合收缩效应在型腔最深处最为显著。显微CT结合图像分析技术是研究牙科复合材料收缩机理的一种新方法。(C)2011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. Light-cured composites undergo shrinkage during polymerization. The aim of this study was to evaluate regional shrinkage within a light-cured composite during polymerization by microcomputed tomography and mechanical properties by nanoindentation in bonded or non-bonded class-I cavity.Methods. Zirconium oxide spherical fillers (30 mu m diameter) were added as markers to a composite resin, filled into a box-shaped class I cavity with or without a bonding agent. The marker fillers were traced in 3D scans obtained by micro-CT before and after polymerization using a software (TRI/3D-BON). The average hardness of the resin composites determined by nanoindentation at each 250 mu m depth was plotted against depth.Results. In the bonded cavity, the filler particles at the top region moved toward the bottom of cavity, but at deeper depths, the direction of vertical movement changed toward the top of cavity (irradiated surface). A significant linear regression was found between filler displacement and composite depth (R(2) = 0.9761). In the unbounded cavity, all the fillers moved toward the light curing source, and a significant power-law regression was found between filler displacement and composite depth (R(2) = 0.849). In both groups, the data scattering increased at regions deeper than 3.5 mm, where the hardness, representing degree of conversion of composite, significantly decreased compared to the surface region.Significance. The magnitude and direction of regional polymerization shrinkage depends on boundary conditions, depth and conversion degree. Polymerization shrinkage effect is most significant at the deepest part of the cavity. The application of micro-CT combined with sophisticated image analysis is a novel approach to investigate shrinkage mechanisms of dental composites. (C) 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.