Making yttria-stabilized tetragonal zirconia translucent.
Making yttria-stabilized tetragonal zirconia translucent.
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DOI：
10.1016/j.dental.2014.08.375
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发表时间：
2014-10
期刊：
影响因子：
--
通讯作者：
Zhang Y
中科院分区：
文献类型：
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作者：
Zhang Y
本研究的目的是为开发具有改进的半透明度的四方氧化钇稳定氧化锆提供设计指南。使用瑞利散射模型检查了 3 mol.% 氧化钇稳定的四方氧化锆 (3Y-TZP) 的半透明度，特别是在线透射率。该理论预测，3Y-TZP 的在线透射率与其厚度、晶粒尺寸和双折射相关。为了达到半透明度的阈值，预测了不同厚度（0.3 – 2.0 mm）的 3Y-TZP 的临界晶粒尺寸。阈值是通过测量一组常见厚度为 1 毫米的牙瓷的平均在线透射率值来定义的。我们的理论预测是用文献中极少数的实验数据之一进行校准的。对于致密、高纯度的氧化锆，其直线透射率随着晶粒尺寸和厚度的减小而增加。为了实现与牙瓷类似的半透明度，需要纳米晶体 3Y-TZP 结构，这主要是由于其双折射大和折射率高。随着 3Y-TZP 厚度的增加，这种晶粒尺寸依赖性变得更加明显。例如，厚度为 1.3 毫米时，半透明 3Y-TZP 的平均晶粒尺寸应为 82 纳米。厚度为 1.5 毫米和 2 毫米时，平均晶粒尺寸需要分别为 77 纳米和 70 纳米。氧化锆修复体具有良好的半透明性和机械性能，可以通过减小其晶粒尺寸来实现。
The aim of this study was to provide a design guideline for developing tetragonal yttria-stabilized zirconia with improved translucency. The translucency, the in-line transmission in particular, of 3 mol.% yttria-stabilized tetragonal zirconia (3Y-TZP) has been examined using the Rayleigh scattering model. The theory predicts that the in-line transmission of 3Y-TZP can be related to its thickness with grain size and birefringence the governing parameters. To achieve a threshold value of translucency, the critical grain size of 3Y-TZP was predicted for various thicknesses (0.3 – 2.0 mm). The threshold value was defined by a measured average in-line transmission value of a suite of dental porcelains with a common thickness of 1 mm. Our theoretical predictions were calibrated with one of the very few experimental data available in the literature. For a dense, high-purity zirconia, its in-line transmission increased with decreasing grain size and thickness. To achieve a translucency similar to that of dental porcelains, a nanocyrstalline 3Y-TZP structure was necessitated, due primarily to its large birefringence and high refractive index. Such a grain size dependence became more pronounced as the 3Y-TZP thickness increased. For example, at a thickness of 1.3 mm, the mean grain size of a translucent 3Y-TZP should be 82 nm. At 1.5 mm and 2 mm thicknesses, the mean grain size needed to be 77 nm and 70 nm, respectively. A promising future for zirconia restorations, with combined translucency and mechanical properties, can be realized by reducing its grain size.