Fractal Analysis of Ceramic FPDs

描述（由申请人提供）：陶瓷假体的断裂面可以使用分形几何来表征，以提供有关材料特性和失效时存在的条件的丰富信息。这种潜在的有用的也没有被广泛采用，因为目前的分形分析方法是劳动密集型的，技术敏感，统计偏差。我们的团队开发了一种新的故障分析方法。它是一种自动、无偏的快速、精确测量断裂表面分形维数增量（D*）的方法。拟议项目旨在验证该工具作为一种使能技术，以允许（1）确定多层结构中的故障起源和（2）确定材料断裂韧性，这两者都有助于改善材料加工。此外，先前的工作使我们假设，（1）和（2）都可以通过分析断裂假体的任何碎片的D* 来确定-即使失效源已经丢失或损坏。此外，当关键缺陷在 断裂表面，我们应该能够估计失效时的应力，这将有助于诊断功能异常和/或非典型残余应力的存在。我们将通过比较我们在两种基准材料（石英玻璃和NIST标准化的Si 3 N4）上的结果与文献中相同材料的值来测试这种技术的准确性。我们将通过验证我们检测三种市售牙科陶瓷中哪一种是双层标本（玻璃陶瓷贴面瓷、氧化锆贴面瓷和氧化锆贴面玻璃陶瓷）中的失效起源的能力来测试该技术的实用性。本计画的主要目标有三：（1）将我们的创新技术应用于具有已知破坏应力水平的标准几何形状的整体及双层挠曲梁试件。(2)我们的创新技术用于全瓷固定局部义齿（包括牙冠和三单元FPD）。(3)确定偏离临床情况的测试条件的影响（单调与循环载荷以及潮湿与干燥环境）。由此产生的信息将对口腔修复领域产生巨大的潜在影响，也可能适用于骨科手术以及汽车、航空航天和半导体行业中使用的陶瓷部件。

DESCRIPTION (provided by applicant): The fracture surfaces of ceramic prostheses can be characterized using fractal geometry to provide a wealth of information about the material properties and the conditions that were present at the time of failure. This potentially useful too is not widely employed because the current methods of fractal analysis are labor intensive, technique sensitive, and statistically biased. Our team has developed a new failure analysis method. It is an automated, unbiased method of rapidly and precisely measuring the fractal dimensional increment (D*) of fracture surfaces. The proposed project aims to validate this tool as an enabling technology to allow (1) determination of the failure origin in multilayered structures and (2) determination of material fracture toughness, both of which are useful in improving material processing. Furthermore, prior work leads us to hypothesize that both (1) and (2) can be determined from analyzing the D* of any fragment of a broken prosthesis - even when the failure origin has been lost or damaged. In addition, when the critical flaw is visible on the fracture surface, we should be able to estimate the stress at failure, which will be useful in diagnosing parafunction and/or the presence of an atypical residual stress. We will test the accuracy of this technique by comparing our results on two benchmark materials (silica glass and NIST standardized Si3N4) to the values in the literature for the same materials. We will test the utility of this technique by verifying our ability to detect which of three commercially availale dental ceramics is the failure origin in bilayered specimens (glass-ceramic veneered with porcelain, zirconia veneered with porcelain, and zirconia veneered with glass-ceramic). There are three overall goals of the proposed project: (1) Validate our innovative technique for use on monolithic and bilayered flexure beam specimens having a standard geometry with known failure stress levels. (2) Validate our innovative technique for use on all-ceramic fixed partial dentures (both crowns and three-unit FPDs). (3) Determine the effects of test conditions that deviate from the clinical case (monotonic vs. cyclic loading and wet vs. dry environment). The resulting information will have a high potential impact on the field of prosthodontics and may also be applicable to ceramic components used in orthopedic surgery and the automotive, aerospace, and semiconductor industries.