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Analysis of tetragonal to monoclinic phase transformation caused by accelerated artificial aging and the effects of microstructure in stabilized zirconia.

机译:加速人工时效引起的四方相向单斜相转变以及稳定氧化锆中微观结构的影响。

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摘要

This investigation addresses the issue that yttria stabilized zirconia is being used as a dental biomaterial without substantial evidence of its long-term viability. Furthermore, stabilized zirconia (SZ) undergoes low temperature degradation (LTD), which can lead to roughening of the surface. A rougher exterior can lead to increased wear of the antagonist in the oral environment. Despite the LTD concerns, SZ is now widely used in restorative dentistry, including full contour crowns.;A comparison of aging methods to determine the role of artificial aging on inducing the transformation has not been extensively studied. Therefore, simulations of the transformation process were investigated by comparing different methods of accelerated aging. The rejected null hypothesis is that the temperature of aging treatment will not affect the time required to cause measurable monoclinic transformation of yttria stabilized zirconia.;The transformation of SZ starts at the surface and progresses inward; however, it is unclear whether the progression is constant for different aging conditions. This investigation analyzed the depth of transformation as a function of aging conditions for stabilized zirconia in the top 5-6 mum from the surface. The rejected null hypothesis is that the transformation amount is constant throughout the first six micrometers from the surface.;The effects of grain size on the amount of monoclinic transformation were also investigated. This study aimed to determine if the grain size of partially stabilized zirconia affects the amount of monoclinic transformation, surface roughness, and property degradation due to aging. The rejected null hypothesis is that the grain size will not affect the amount of monoclinic transformation, thus have no effect on surface roughening or property degradation.;The final part of this study addresses the wear of enamel when opposing zirconia by observing how grain size and aging affected the wear rate of an enamel antagonist. The rejected null hypothesis is that neither zirconia grain size, nor aging condition affects the wear of an enamel antagonist.
机译:这项研究解决了氧化钇稳定的氧化锆被用作牙科生物材料的问题,而没有其长期生存能力的充分证据。此外,稳定的氧化锆(SZ)经历低温降解(LTD),这可能导致表面粗糙。较粗糙的外部会导致拮抗剂在口腔环境中的磨损增加。尽管有LTD的顾虑,但SZ现在已广泛用于包括全轮廓牙冠在内的修复牙科中。尚未广泛研究确定老化方法对人工老化在诱导转化中的作用的比较。因此,通过比较不同的加速老化方法,研究了转变过程的模拟。被否定的零假设是老化处理的温度不会影响引起氧化钇稳定的氧化锆的单斜晶转变的所需时间。SZ的转变始于表面并向内进行;然而,尚不清楚对于不同的老化条件,进展是否恒定。这项研究分析了表面顶部5-6毫米处稳定氧化锆的转变深度与老化条件的关系。被否定的零假设是,从表面开始的前六个微米,相变量是恒定的。;还研究了晶粒尺寸对单斜晶相变量的影响。这项研究旨在确定部分稳定的氧化锆的晶粒尺寸是否会影响单斜相转变的数量,表面粗糙度以及由于老化而导致的性能下降。被否定的零假设是,晶粒尺寸不会影响单斜晶相转变的量,因此对表面粗糙化或性能退化没有影响。老化影响搪瓷拮抗剂的磨损率。被否定的零假设是氧化锆的晶粒尺寸和老化条件都不会影响搪瓷拮抗剂的磨损。

著录项

  • 作者

    Lucas, Thomas J.;

  • 作者单位

    The University of Alabama at Birmingham.;

  • 授予单位 The University of Alabama at Birmingham.;
  • 学科 Materials science.;Dentistry.
  • 学位 Ph.D.
  • 年度 2015
  • 页码 109 p.
  • 总页数 109
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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