A comparison of fatigue crack growth in human enamel and hydroxyapatite.
A comparison of fatigue crack growth in human enamel and hydroxyapatite.
复制标题
比较人搪瓷和羟基磷灰石疲劳裂纹的生长。
DOI：
10.1016/j.biomaterials.2008.08.019
复制
发表时间：
2008-12
期刊：
影响因子：
14
通讯作者：
Arola, Dwayne D.
中科院分区：
文献类型：
--
作者：
Bajaj, Devendra;Nazari, Ahmad;Eidelman, Naomi;Arola, Dwayne D.
在人类牙齿的釉质中经常观察到裂纹和银纹，但它们很少导致牙齿断裂。本研究评估了人牙釉质中的疲劳裂纹生长，并将其与具有相似结晶度、化学性质和密度的烧结羟基磷灰石（HAp）的疲劳响应进行了比较。制备包含一小片牙釉质（N=8）或HAp（N=6）的微型嵌入紧凑拉伸（CT）样本。试样经受I型循环载荷，并使用巴黎定律模拟稳态裂纹扩展响应。结果表明，搪瓷的疲劳裂纹扩展指数m（m = 7.7±1.0）与HAp相似（m = 7.9±1.4），而搪瓷的裂纹扩展系数（C）（C=8.7E-04（mm/cycle）·（MPa·m0.5）-m）显著低于HAp（C = 2.0E+00（mm/cycle）·（MPa·m0.5）-m）（p<0.0001）。断裂表面的显微照片表明，裂纹生长在搪瓷发生主要沿着棱柱边界。在交叉区域，显微组织促进微裂纹、裂纹桥接、裂纹偏转和裂纹分叉。协同工作，这些机制增加了裂纹扩展阻力，并导致对裂纹扩展的敏感性（m）类似于骨，低于人类牙本质。在烧结HAp的裂纹生长响应中没有观察到这些增韧机制。虽然釉质是人体中矿化程度最高的组织，但棱柱的微观结构排列促进了对裂纹生长的特殊抵抗力。
Cracks and craze lines are often observed in the enamel of human teeth, but they rarely cause tooth fracture. The present study evaluates fatigue crack growth in human enamel, and compares that to the fatigue response of sintered hydroxyapatite (HAp) with similar crystallinity, chemistry and density. Miniature inset compact tension (CT) specimens were prepared that embodied a small piece of enamel (N=8) or HAp (N=6). The specimens were subjected to mode I cyclic loads and the steady state crack growth responses were modeled using the Paris Law. Results showed that the fatigue crack growth exponent (m) for enamel (m = 7.7±1.0) was similar to that for HAp (m = 7.9±1.4), whereas the crack growth coefficient (C) for enamel (C=8.7E-04 (mm/cycle)·(MPa·m0.5)-m) was significantly lower (p<0.0001) than that for HAp (C = 2.0E+00 (mm/cycle)·(MPa·m0.5)-m). Micrographs of the fracture surfaces showed that crack growth in the enamel occurred primarily along the prism boundaries. In regions of decussation, the microstructure promoted microcracking, crack bridging, crack deflection and crack bifurcation. Working in concert, these mechanisms increased the crack growth resistance and resulted in a sensitivity to crack growth (m) similar to bone and lower than that of human dentin. These mechanisms of toughening were not observed in the crack growth response of the sintered HAp. While enamel is the most highly mineralized tissue of the human body, the microstructural arrangement of the prisms promotes exceptional resistance to crack growth.
登录
查看更多内容
DOI：
10.1002/jbm.b.30927
发表时间：
2008-04-01
影响因子：
3.4
作者：
Bajaj, D.;Sundaram, N.;Arola, D.
通讯作者：
Arola, D.
影响因子：
14
作者：
Benaqqa, C;Chevalier, J;Fantozzi, G
通讯作者：
Fantozzi, G
影响因子：
4.6
作者：
FOWLER, BO
通讯作者：
FOWLER, BO
影响因子：
7.6
作者：
SKOBE, Z;STERN, S
通讯作者：
STERN, S
影响因子：
14
作者：
Kruzic, JJ;Nalla, RK;Ritchie, RO
通讯作者：
Ritchie, RO