Influence of thickness and cooling rate on development of spontaneous cracks in porcelain/zirconia structures
Influence of thickness and cooling rate on development of spontaneous cracks in porcelain/zirconia structures
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DOI：
10.1111/j.1834-7819.2010.01239.x
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发表时间：
2010-09-01
影响因子：
2.1
通讯作者：
Klineberg, I.
中科院分区：
文献类型：
--
作者：
Guazzato, M.;Walton, T. R.;Klineberg, I.
背景资料：临床研究报告的氧化锆基牙列的结果表明，氧化锆框架的强度足以承受咀嚼力。然而，一个显着的发生率内聚断裂的贴面瓷已报告。本研究的目的是调查自发裂纹的发展（碎裂，破裂）的范围内的瓷贴面的氧化锆核心的厚度和冷却速率的变化引起的热应力的结果。测试的假设是，裂纹的发病率将增加单板厚度和更快的冷却rate.Methods：氧化锆球（直径7.8毫米）与1.5克（厚度比1：2）和2.5克（厚度比1：1）的五个标称兼容的市售瓷贴面。制造商的烧制周期和快速冷却烧制cyclefollow.Results：多元回归分析显示，裂纹的发生和三个协变量（材料，厚度和冷却速率）之间呈正相关。裂纹和破裂的贴面瓷的发生率增加了一个更快的冷却速度和增加的厚度的标本在三个porcelain-zirconia combination.Conclusions：裂纹的发生率增加，增加瓷贴面厚度和更快的冷却速度在名义上兼容的瓷/氧化锆系统中的几何配置的试样测试。
Background: Clinical studies reporting the outcome of zirconia-based restorations indicate that the strength of the zirconia frameworks is sufficient to withstand masticatory forces. However, a significant incidence of cohesive fracture of the veneering porcelain has been reported. The aim of this study was to investigate spontaneous crack development (chipping, rupture) in a range of porcelains veneered to a zirconia core as a result of thermal stresses induced by changes in thickness and cooling rate. The hypothesis tested was that crack incidence would increase with increased veneer thickness and faster cooling rates.Methods: Zirconia spheres (diameter 7.8 mm) were veneered with 1.5 gm (thickness ratio 1: 2) and 2.5 gm (thickness ratio 1: 1) of five nominally compatible commercially available porcelains. The manufacturers' firing cycles and a rapid cooling firing cycle were followed.Results: Multiple regression analysis showed positive associations between the occurrence of cracks and the three covariates (materials, thickness and cooling rate). The incidence of cracks and rupture of the veneering porcelain increased with a faster cooling rate and increased thickness of the specimens in three porcelain-zirconia combinations.Conclusions: Crack incidence increased with increased porcelain veneer thickness and faster cooling rates in nominally compatible porcelain/zirconia systems in the geometrically configured specimens tested.