Finite-element modeling of the anthropoid mandible: The effects of altered boundary conditions
Finite-element modeling of the anthropoid mandible: The effects of altered boundary conditions
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DOI：
10.1002/ar.a.20166
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发表时间：
2005-04-01
期刊：
影响因子：
--
通讯作者：
Rapoff, AJ
中科院分区：
文献类型：
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作者：
Marinescu, R;Daegling, DJ;Rapoff, AJ
有限元建模为描述颅骨的应力环境提供了一种全场方法。然而，有限元模型的实用性仍然是不确定的，因为我们忽视了这种模型是否有效地描述了应力和应变状态。例如，被选择来代表体内力学环境的边界条件的影响在很大程度上是未知的。为了验证模型的有效性，我们对新鲜的成年恒河猴下颌骨进行了体外应变计实验，通过有限元分析模拟了一种简化的加载模式。在不同的材料和结构复杂性条件下，我们构建了齿形和无齿模型，以测量边界条件(力方向和节点约束)的变化对应变值在量规位置预测的影响。我们的结果为从体内应变数据验证有限元模型时遇到的困难提供了一个前瞻性的评估。载荷施加方向上的微小误差会导致预测应变的显著变化。各向同性模型虽然方便，但与实验菌株的一致性较差，而非均质正交异性模型预测的菌株与这些数据更一致。最重要的是，我们发现无牙模型在重建实验菌株方面比有齿模型表现得更好。虽然这一结果无疑与我们未能建立牙周韧带模型有关，但我们将这一发现解释为，在没有咬合载荷的情况下，牙槽内的牙齿对下颌骨的结构僵硬没有显著贡献。(C)2005年Wiley-Liss，Inc.
Finite-element modeling provides a full-field method for describing the stress environment of the skull. The utility of finite-element models, however, remains uncertain given our ignorance of whether such models validly portray states of stress and strain. For example, the effects of boundary conditions that are chosen to represent the mechanical environment in vivo are largely unknown. We conducted an in vitro strain gauge experiment on a fresh, fully dentate adult mandible of Macaca fascicularis to model a simplified loading regime by finite-element analysis for purposes of model validation. Under various conditions of material and structural complexity, we constructed dentate and edentulous models to measure the effects of changing boundary conditions (force orientation and nodal constraints) on strain values predicted at the gauge location. Our results offer a prospective assessment of the difficulties encountered when attempting to validate finite-element models from in vivo strain data. Small errors in the direction of load application produce significant changes in predicted strains. An isotropic model, although convenient, shows poor agreement with experimental strains, while a heterogeneous orthotropic model predicts strains that are more congruent with these data. Most significantly, we find that an edentulous model performs better than a dentate one in recreating the experimental strains. While this result is undoubtedly tied to our failure to model the periodontal ligament, we interpret the finding to mean that in the absence of occlusal loads, teeth within alveoli do not contribute significantly to the structural stiffness of the mandible. (c) 2005 Wiley-Liss, Inc.