American Dental Association Foundation, Paffenbarger Research Center, National Institute of Standards and Technology, Gaithersburg, MD, USA.
Dent Mater. 2010 Jan;26(1):13-20. doi: 10.1016/j.dental.2009.08.005.
To investigate the chipping resistance of veneered zirconia specimens and compare it to the chipping resistance of porcelain fused to metal (PFM) specimens.
Veneered zirconia and PFM bar specimens were prepared in clinically relevant thicknesses. The specimen edges were chipped with different magnitude forces, producing chips of various sizes. The range of sizes included small chips that did not penetrate all the way through the veneers to the substrates, and also chips that were very large and reached the zirconia or metal substrates. The relationship between force magnitude and chip size (edge distance) was graphed. The resulting curves were compared for the veneered zirconia and PFM specimens. Knoop hardness vs. force graphs for the veneers and substrates were also obtained.
The zirconia and PFM veneer chipping data followed a power law (coefficient of determination, R(2)>0.93) as expected from the literature. The curves overlapped within the combined data scatter, indicating similar resistance to chipping. The chips made in both types of specimens detached and did not penetrate into the substrate when they reached the veneer/substrate intersections. The hardness-load curves for the veneers and substrates all exhibited an indentation size effect (ISE) at low loads. The Knoop hardness values with uncertainties of +/-one standard deviation at 4N loads for the metal, zirconia, and the metal and zirconia veneers are: (2.02+/-0.08, 12.01+/-0.39, 4.24+/-0.16 and 4.36+/-0.02GPa), respectively, with no statistically significant difference between the veneers (Tukey pairwise comparison at 0.95 family confidence).
This work indicates that a similar resistance to chipping might be expected for veneered zirconia and PFM restorations, in spite of the large difference in substrate hardness. Differences in susceptibility to chip spalling were not detected, but the chips in both specimen types detached off the sides in a similar manner instead of extending into the substrates.
研究贴面氧化锆试件的抗碎裂性，并与金属烤瓷熔附金属（PFM）试件的抗碎裂性进行比较。
制备临床相关厚度的贴面氧化锆和 PFM 棒试件。用不同大小的力使试件边缘碎裂，产生各种大小的碎片。碎片的大小范围包括没有完全穿透贴面到达基底的小碎片，以及非常大的到达氧化锆或金属基底的碎片。绘制力大小与碎片大小（边缘距离）之间的关系图。比较贴面氧化锆和 PFM 试件的曲线。还获得了贴面和基底的努氏硬度与力图。
氧化锆和 PFM 贴面碎裂数据符合幂律（文献报道的决定系数，R²>0.93）。在合并数据的散射范围内，曲线重叠，表明抗碎裂性相似。在两种类型的试件中，当碎片到达贴面/基底交界处时，它们会分离并且不会穿透到基底中。在低载荷下，所有贴面和基底的硬度-载荷曲线都表现出压痕尺寸效应（ISE）。在 4N 载荷下，金属、氧化锆和金属/氧化锆贴面的不确定度为±1 个标准差的努氏硬度值分别为：（2.02±0.08、12.01±0.39、4.24±0.16 和 4.36±0.02GPa），在贴面之间没有统计学上的显著差异（在 0.95 置信水平下的 Tukey 两两比较）。
尽管基底硬度有很大差异，但本研究表明，对于贴面氧化锆和 PFM 修复体，可能会有相似的抗碎裂性。没有检测到碎片剥落的敏感性差异，但两种类型的试件的碎片都以相似的方式从侧面脱落，而不是延伸到基底中。
