Aging and the reduction in fracture toughness of human dentin.
Aging and the reduction in fracture toughness of human dentin.
复制标题
衰老和人牙本质骨折韧性的减小。
DOI：
10.1016/j.jmbbm.2009.01.008
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发表时间：
2009-10
影响因子：
3.9
通讯作者：
Arola, D.
中科院分区：
文献类型：
--
作者：
Nazari, A.;Bajaj, D.;Zhang, D.;Romberg, E.;Arola, D.
对18岁至83岁患者的组织进行了冠状牙本质抗裂生长的评估。在I型准静态加载下，在垂直于标称小管方向的临床相关长度（0≤a≤1 mm）上实现了稳定的裂缝扩展。结果表明，人牙本质的裂纹扩展阻力随扩展而增加（即r曲线上升），韧性的起始（Ko）和平台（Kp）分量随患者年龄的增加而显著降低。在幼牙本质（18≤年龄≤35岁）中，裂纹扩展阻力从扩展开始（Ko =1.34 MPa·m0.5）到最大或“平台”韧性（Kp = 1.65 MPa·m0.5）增加25%。老年牙本质（55岁≤年龄）的抗裂纹扩展能力从Ko = 1.08 MPa·m0.5增加到Kp = 1.17 MPa·m0.5，随扩展增加幅度小于10%。在年轻的牙本质增韧是通过矿化胶原基质的非弹性变形和小管周围袖口的微开裂的结合来实现的。这些机制通过未断裂的组织韧带的发育和后路裂缝桥接促进了进一步的增韧。随着时效的变化，微观组织的变化降低了微管的近尖端非弹性变形和微裂纹的能力，从而抑制了不断裂韧带的形成和外部增韧的程度。
An evaluation of the crack growth resistance of human coronal dentin was performed on tissue obtained from patients between ages 18 and 83. Stable crack extension was achieved over clinically relevant lengths (0 ≤ a ≤1 mm) under Mode I quasi-static loading and perpendicular to the nominal tubule direction. Results distinguished that human dentin exhibits an increase in crack growth resistance with extension (i.e. rising R-curve) and that there is a significant reduction in both the initiation (Ko) and plateau (Kp) components of toughness with patient age. In the young dentin (18≤age≤35) there was a 25 % increase in the crack growth resistance from the onset of extension (Ko =1.34 MPa·m0.5) to the maximum or “plateau” toughness (Kp = 1.65 MPa·m0.5). In comparison, the crack growth resistance of the old dentin (55≤age) increased with extension by less than 10 % from Ko = 1.08 MPa·m0.5 to Kp = 1.17 MPa·m0.5. In young dentin toughening was achieved by a combination of inelastic deformation of the mineralized collagen matrix and microcracking of the peritubular cuffs. These mechanisms facilitated further toughening via the development of unbroken ligaments of tissue and posterior crack-bridging. Microstructural changes with aging decreased the capacity for near-tip inelastic deformation and microcracking of the tubules, which in turn suppressed the formation of unbroken ligaments and the degree of extrinsic toughening.
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影响因子：
14
作者：
Porter, AE;Nalla, RK;Ritchie, RO
通讯作者：
Ritchie, RO
影响因子：
14
作者：
Arola, D;Reprogel, RK
通讯作者：
Reprogel, RK
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：
3
作者：
Mjor, IA;Nordahl, I
通讯作者：
Nordahl, I
影响因子：
6.2
作者：
Ager, Joel W., III;Nalla, Ravi K.;Ritchie, Robert O.
通讯作者：
Ritchie, Robert O.