An examination of fatigue striations in human dentin:: In vitro and In vivo
An examination of fatigue striations in human dentin:: In vitro and In vivo
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DOI：
10.1002/jbm.b.30927
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发表时间：
2008-04-01
影响因子：
3.4
通讯作者：
Arola, D.
中科院分区：
文献类型：
--
作者：
Bajaj, D.;Sundaram, N.;Arola, D.
虽然条纹常被用来评估工程材料的疲劳裂纹扩展，但还没有被用于研究硬组织的断裂力学。这项研究的主要目的是评估疲劳裂纹在人类牙齿牙本质中的扩展引起的条纹。从年轻(17=50岁)患者的磨牙冠向牙本质中获取紧凑型拉伸(CT)标本，对其进行I型循环加载。用扫描电子显微镜(SEM)和接触式轮廓仪观察了断口上明显的条纹。在修复磨牙的断裂面上也检查了发展成不良活体的疲劳裂纹扩展条纹。CT样品表面轮廓的功率谱分析表明，条纹间距在50到170双关之间。老年人牙本质平均间距(130.23微米)显著大于年轻牙本质(88.13微米)(p<；0.001)。修复牙齿中的疲劳条纹显示出与体外发育的一致的特征，间距从59到95 Pun。与金属不同，牙本质中的条纹是在1×10(3)至1×10(5)周期的循环加载后形成的。使用Bates-Clark方程对条纹间距的定量评估表明，修复牙内的循环裂纹扩展发生在0.7 Mpa中心点m(0.5)附近的应力0.5强度范围内，应力范围类似于12 Mpa。(C)2007年威利期刊公司。
Although striations are often used in evaluating fatigue crack growth in engineering materials, they have not been used in studying the mechanics of fracture in hard tissues. The primary objective of this study was to evaluate the striations resulting from fatigue crack growth in the dentin of human teeth. Compact tension (CT) specimens obtained from the coronal dentin of molars from young (17 = 50 years) patients were subjected to cyclic Mode I loads. Striations evident on the fracture surfaces were examined using a scanning electron microscope (SEM) and contact profilometer. Fatigue crack growth striations that developed ill vivo were also examined on fracture surfaces of restored molars. A power spectrum analysis of surface profiles from the CT specimens showed that the striation spacing ranged from 50 to 170 pun. The average spacing in the dentin of seniors (130 23 mu m) was significantly larger (p < 0.001) than that in young dentin (88 13 mu m). Fatigue striations in the restored teeth exhibited features that were consistent with those that developed in vitro and a spacing ranging from 59 to 95 Pun. Unlike metals, the striations in dentin developed after a period of cyclic loading that ranged from 1 X 10(3) to 1 X 10(5) cycles. A quantitative evaluation of the striation spacing using the Bates-Clark equation suggested that cyclic crack growth within the restored teeth occurred at a stress 0.5 intensity range near 0.7 MPa center dot m(0.5), and a stress range of similar to 12 MPa. (c) 2007 Wiley Periodicals, Inc.