Sakar-Deliormanli Aylin, Güden Mustafa
Materials Science and Engineering Program, Izmir Institute of Technology, Urla, Izmir, Turkey.
J Biomed Mater Res B Appl Biomater. 2006 Feb;76(2):257-64. doi: 10.1002/jbm.b.30371.
The main objective of this study was to measure the fracture toughness of the human teeth enamel using the microindentation technique and to compare the results calculated from the equations developed for Palmqvist and radial-median cracks. Vickers microhardness measurements of dental ceramic (alumina) and human teeth were performed using indentation fracture method. The fracture toughness of enamel was calculated using different equations reported in the literature. Vickers microhardness of the sintered alumina specimen (98.8% theoretical density) was measured to be 14.92 GPa under 9.8 N indentation load. Three equations based on the radial-median cracks were found to be applicable for the fracture toughness determination of the enamel. Results show that indentation fracture method is adequate to measure microhardness and fracture toughness of dental materials. However the calculation of fracture toughness depended on the nature of the cracks and also on the location of the indentation. Therefore, it is necessary to identify the crack profile and to select the appropriate equation for accurate fracture toughness values.
本研究的主要目的是使用微压痕技术测量人类牙齿釉质的断裂韧性，并比较根据为帕尔姆奎斯特裂纹和径向-中位裂纹所开发的公式计算得出的结果。采用压痕断裂法对牙科陶瓷（氧化铝）和人类牙齿进行维氏显微硬度测量。使用文献中报道的不同公式计算釉质的断裂韧性。在9.8 N压痕载荷下，烧结氧化铝试样（理论密度为98.8%）的维氏显微硬度测量值为14.92 GPa。发现基于径向-中位裂纹的三个公式适用于釉质断裂韧性的测定。结果表明，压痕断裂法足以测量牙科材料的显微硬度和断裂韧性。然而，断裂韧性的计算取决于裂纹的性质以及压痕的位置。因此，有必要识别裂纹轮廓并选择合适的公式以获得准确的断裂韧性值。
