Restorative Dentistry Area, Dental School, Federal University of Goiás, Goiânia, GO, Brazil.
J Appl Oral Sci. 2010 Sep-Oct;18(5):467-76. doi: 10.1590/s1678-77572010000500007.
In the most recent decades, several developments have been made on impression materials' composition, but there are very few radiodensity studies in the literature. It is expected that an acceptable degree of radiodensity would enable the detection of small fragments left inside gingival sulcus or root canals.
The aim of this study was to determine the radiodensity of different impression materials, and to compare them to human and bovine enamel and dentin.
Twenty-five impression materials, from 5 classes, were studied: addition and condensation silicones, polyether, polysulfides and alginates. Five 1-mm-thick samples of each material and tooth structure were produced. Each sample was evaluated 3 times (N=15), being exposed to x-ray over a phosphor plate of Digora digital system, and radiodensity was obtained by the software Digora for Windows 2.5 Rev 0. An aluminum stepwedge served as a control. Data were subjected to Kruskal-Wallis and Dunn's method (α=0.05).
Different materials and respective classes had a different behavior with respect to radiodensity. Polysulfides showed high values of radiodensity, comparable to human enamel (p>0.05), but not to bovine enamel (p<0.05). Human dentin was similar only to a heavy-body addition silicon material, but bovine dentin was similar to several materials. Generally, heavy-body materials showed higher radiodensity than light-body ones (p<0.05).
Impression materials' radiodensity are influenced by composition, and almost all of them would present a difficult detection against enamel or dentin background in radiographic examinations.
在最近几十年，印模材料的组成有了一些发展，但文献中几乎没有关于射线密度的研究。人们期望一定程度的射线密度可以使龈沟或根管内残留的小碎片得以检测。
本研究旨在确定不同印模材料的射线密度，并将其与人类和牛的牙釉质和牙本质进行比较。
研究了五类 25 种印模材料：加成型和缩合型硅橡胶、聚醚、聚硫和藻酸盐。每种材料和牙体结构都制作了 5 个 1mm 厚的样本。每个样本评估 3 次（N=15），通过 Digora 数字系统的磷光板对 X 射线进行曝光，通过 Digora for Windows 2.5 Rev 0 软件获得射线密度。铝阶梯片用作对照。数据采用 Kruskal-Wallis 和 Dunn 方法（α=0.05）进行分析。
不同的材料和相应的类别在射线密度方面表现出不同的行为。聚硫类材料显示出较高的射线密度，与人的牙釉质相当（p>0.05），但与牛的牙釉质不同（p<0.05）。人类牙本质仅与重体加成型硅橡胶相似，但牛牙本质与多种材料相似。一般来说，重体材料的射线密度高于轻体材料（p<0.05）。
印模材料的射线密度受组成影响，在放射学检查中，几乎所有材料的检测都将难以与牙釉质或牙本质背景区分。
