Name: a finite element approach for locating the center of resistance of maxillary teeth
Uploaded: 2020-04-08T13:00:00
Description: Watch this Scientific Journal Video about A Finite Element Approach for Locating the Center of Resistance of Maxillary Teeth at JoVE.com

作者感谢查尔斯·伯斯顿基金会奖对该项目的支持。

获得机构审查委员会豁免，以评价在口腔和颌面放射科存档的CBCT卷（IRB第17-071S-2号）。
1. 音量选择和标准
<ol><li>获取 CBCT 头部和面部16的图像。</li>
	<li>检查图像的齿对齐、缺失齿、体素尺寸、视野和图像的整体质量。</li>
	<li>确保体素尺寸不超过 350 μm（0.35 毫米）。</li>
</ol>2. 牙齿和骨骼的分割
<ol><li>将 CBCT 映像的原始 DICOM 文件加载?...

<ol>
	<li>Smith, R. J., Burstone, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanics+of+tooth+movement.">Mechanics of tooth movement.</a> American Journal of Orthodontics. 85 (4), 294-307 (1984).</li><li>Christiansen, R. L., Burstone, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Centers+of+rotation+within+the+periodontal+space.">Centers of rotation within the periodontal space.</a> American Journal of Orthodontics. 55 (4), 353-369 (1969).</li><li>Tanne, K., Nagataki, T., Inoue, Y., Sakuda, M., Burstone, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterns+of+initial+tooth+displacements+associated+with+various+root+lengths+and+alveolar+bone+heights.">Patterns of initial tooth displacements associated with various root lengths and alveolar bone heights.</a> American Journal of Orthodontics and Dentofacial Orthopedics. 100 (1), 66-71 (1991).</li><li>Burstone, C. J., Pryputniewicz, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Holographic+determination+of+centers+of+rotation+produced+by+orthodontic+forces.">Holographic determination of centers of rotation produced by orthodontic forces.</a> American Journal of Orthodontics. 77 (4), 396-409 (1980).</li><li>Dermaut, L. R., Kleutghen, J. P., De Clerck, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+determination+of+the+Cres+of+the+upper+first+molar+in+a+macerated,+dry+human+skull+submitted+to+horizontal+headgear+traction.">Experimental determination of the Cres of the upper first molar in a macerated, dry human skull submitted to horizontal headgear traction.</a> American Journal of Orthodontics and Dentofacial Orthopedics. 90 (1), 29-36 (1986).</li><li>Tanne, K., Sakuda, M., Burstone, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+finite+element+analysis+for+stress+in+the+periodontal+tissue+by+orthodontic+forces.">Three-dimensional finite element analysis for stress in the periodontal tissue by orthodontic forces.</a> American Journal of Orthodontics and Dentofacial Orthopedics. 92 (6), 499-505 (1987).</li><li>Meyer, B. N., Chen, J., Katona, T. 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F., Budiman, A., Burstone, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axes+of+resistance+for+tooth+movement:+Does+the+Cres+exist+in+3-dimensional+space?.">Axes of resistance for tooth movement: Does the Cres exist in 3-dimensional space?.</a> American Journal of Orthodontics and Dentofacial Orthopedics. 143 (2), 163-172 (2013).</li><li>Ammar, H. H., Ngan, P., Crout, R. J., Mucino, V. H., Mukdadi, O. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+modeling+and+finite+element+analysis+in+treatment+planning+for+orthodontic+tooth+movement.">Three-dimensional modeling and finite element analysis in treatment planning for orthodontic tooth movement.</a> American Journal of Orthodontics and Dentofacial Orthopedics. 139 (1), 59-71 (2011).</li><li>Sia, S., Koga, Y., Yoshida, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determining+the+center+of+resistance+of+maxillary+anterior+teeth+subjected+to+retraction+forces+in+sliding+mechanics.+An+in+vivo+study.">Determining the center of resistance of maxillary anterior teeth subjected to retraction forces in sliding mechanics. An in vivo study.</a> Angle Orthodontics. 77 (6), 999-1003 (2007).</li><li>Cattaneo, P. M., Dalstra, M., Melsen, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moment-to-force+ratio,+center+of+rotation,+and+force+level:+a+finite+element+study+predicting+their+interdependency+for+simulated+orthodontic+loading+regimens.">Moment-to-force ratio, center of rotation, and force level: a finite element study predicting their interdependency for simulated orthodontic loading regimens.</a> American Journal of Orthodontics and Dentofacial Orthopedics. 133 (5), 681-689 (2008).</li><li>Tominaga, J. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+play+between+bracket+and+archwire+on+anterior+tooth+movement+in+sliding+mechanics:+A+three-dimensional+finite+element+study.">Effect of play between bracket and archwire on anterior tooth movement in sliding mechanics: A three-dimensional finite element study.</a> Journal of Dental Biomechanics. 3, 1758736012461269 (2012).</li><li>Cai, Y., Yang, X., He, B., Yao, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Finite+element+method+analysis+of+the+periodontal+ligament+in+mandibular+canine+movement+with+transparent+tooth+correction+treatment.">Finite element method analysis of the periodontal ligament in mandibular canine movement with transparent tooth correction treatment.</a> BMC Oral Health. 15 (106), (2015).</li><li>Pauwels, R., Araki, K., Siewerdsen, J. H., Thongvigitmanee, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technical+aspects+of+dental+CBCT:+state+of+the+art.">Technical aspects of dental CBCT: state of the art.</a> Dentomaxillofacial Radiology. 44 (1), 20140224 (2015).</li><li>Farah, J. W., Craig, R. G., Sikarskie, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoelastic+and+finite+element+stress+analysis+of+a+restored+axisymmetric+first+molar.">Photoelastic and finite element stress analysis of a restored axisymmetric first molar.</a> Journal of Biomechanics. 6 (5), 511-520 (1973).</li><li>van Driel, W. D., van Leeuwen, E. J., Von den Hoff, J. W., Maltha, J. C., Kuijpers-Jagtman, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Time-dependent+mechanical+behavior+of+the+periodontal+ligament.">Time-dependent mechanical behavior of the periodontal ligament.</a> Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine. 214 (5), 497-504 (2000).</li><li>Bourauel, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simulation+of+orthodontic+tooth+movements.+A+comparison+of+numerical+models.">Simulation of orthodontic tooth movements. A comparison of numerical models.</a> Journal of Orofacial Orthopedics. 60 (2), 136-151 (1999).</li><li>Schneider, J., Geiger, M., Sander, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Numerical+experiments+on+longtime+orthodontic+tooth+movement.">Numerical experiments on longtime orthodontic tooth movement.</a> American Journal of Orthodontics and Dentofacial Orthopedics. 121 (3), 257-265 (2002).</li><li>Ten Cate, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Oral histology, development, structure and function (5th ed). , (1998).</li><li>McCormack, S. W., Witzel, U., Watson, P. J., Fagan, M. J., Gr&#246;ning, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Biomechanical+Function+of+Periodontal+Ligament+Fibres+in+Orthodontic+Tooth+Movement.">The Biomechanical Function of Periodontal Ligament Fibres in Orthodontic Tooth Movement.</a> PLoS One. 9 (7), e102387 (2014).</li><li>Huang, H., Tang, W., Yan, B., Wu, B., Cao, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+responses+of+the+periodontal+ligament+based+on+an+exponential+hyperelastic+model:+a+combined+experimental+and+finite+element+method.">Mechanical responses of the periodontal ligament based on an exponential hyperelastic model: a combined experimental and finite element method.</a> Computer Methods in Biomechanics and Biomedical Engineering. 19 (2), 188-198 (2016).</li><li>Yang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+device+for+measuring+density+of+jaw+bones.">A new device for measuring density of jaw bones.</a> Dentomaxillofacial Radiology. 31 (5), 313-316 (2002).</li><li>Gradl, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mass+density+measurement+of+mineralized+tissue+with+grating-based+X-ray+phase+tomography.">Mass density measurement of mineralized tissue with grating-based X-ray phase tomography.</a> PLoS One. 11 (12), e01677979 (2016).</li><li>Jiang, F., Kula, K., Chen, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimating+the+location+of+the+center+of+resistance+of+canines.">Estimating the location of the center of resistance of canines.</a> Angle Orthodontics. 86 (3), 365-371 (2016).</li><li>Nyashin, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Center+of+resistance+and+center+of+rotation+of+a+tooth:+experimental+determination,+computer+simulation+and+the+effect+of+tissue+nonlinearity.">Center of resistance and center of rotation of a tooth: experimental determination, computer simulation and the effect of tissue nonlinearity.</a> Computer Methods in Biomechanics and Biomedical Engineering. 19, 229-239 (2016).</li><li>Toms, S. R., Eberhardt, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+nonlinear+finite+element+analysis+of+the+periodontal+ligament+under+orthodontic+tooth+loading.">A nonlinear finite element analysis of the periodontal ligament under orthodontic tooth loading.</a> American Journal of Orthodontics and Dentofacial Orthopedics. 123 (6), 657-665 (2003).</li><li>Osipenko, M. A., Nyashin, M. Y., Nyashin, Y. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Centre+of+resistance+and+centre+of+rotation+of+a+tooth:+the+definitions,+conditions+of+existence,+properties.">Centre of resistance and centre of rotation of a tooth: the definitions, conditions of existence, properties.</a> Russian Journal of Biomechanics. 3 (1), 5-15 (1999).</li><li>Dathe, H., N&#228;gerl, H., Dietmar, K. 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这项研究展示了一套工具，以建立一个一致的工作流程，有限元分析模型的颌骨牙齿模型派生自病人的CBCT图像，以确定他们的CRES。对于临床医生来说，一个清晰而直接的颌长牙齿CRES图谱将是一个宝贵的临床工具，用于规划牙齿运动和预测副作用。有限元法于,1973年17月在牙科生物力学研究中引入，此后应用于分析眼拉支撑结构6、7、8、9、10、11、12</s...

牙齿或牙齿段的阻力中心（CRES）类似于自由体的质量中心。这是一个借用硬体力学领域的术语。当在CRES施加一个力时，在力作用线方向上转换牙齿时，会发生11、2。2CRES的位置不仅取决于牙齿的解剖结构及其特性，还取决于牙齿的环境（例如，牙周韧带、周围骨骼、相邻牙齿）。牙齿是一个克制的身体，使其CRES类似于自由体的质量中心。在操作器具时，大多数正畸师会考虑力向量与牙齿或一组牙齿的CRES的关系。事实上，物体在提交到单个力时是否会显示倾翻或身体运动，主要取决于物体的 CRES的位置以及力矢量和 CRES之间的距离。如果能准确预测，治疗效果将大大改善。因此，对CRES的准确估计可以大大提高正畸牙齿运动的效率。
数十年来，正畸领域一直在重新审视有关给定牙齿、段或拱门,,11、2、3、4、5、6、7、8、9、10、11、122,3,4的,7,8,9,10,11,12CRES位置的研究。56然而，这些研究在许多方面都限制了它们的方法。大多数研究只确定了只有几颗牙齿的CRES，排除了大多数牙齿。例如，对最大中央切口和最大切口段进行了相当广泛的评估。另一方面，只有很少的研究，对最大单体单子和第一摩尔，没有为剩余的牙齿。此外，许多这些研究已经根据牙齿的通用解剖数据、二维（2D）放射图的测量和2D图纸8的计算来确定了CRES的位置。此外，一些目前的文献使用通用模型或三维（3D）扫描的牙本质模型，而不是人类数据44，8。8随着正畸学转向3D技术来规划牙齿运动，重新审视这个概念以培养对牙齿运动的3D科学理解至关重要。
随着技术进步导致计算能力和建模能力的提高，创建和研究更复杂的模型的能力也有所提高。计算机断层扫描扫描和锥形束计算机断层扫描（CBCT）扫描的引入将2D世界模型和计算推入3D。计算能力和软件复杂性的同步增加使得研究人员能够使用3D放射图提取精确的解剖模型，用于高级软件，以分割牙齿、骨骼、牙周韧带（PDL）以及各种其他结构787、8、9、10、13、14、15。13,14,159,10,,,这些分段结构可以转换为虚拟网格，用于工程软件，以计算系统在施加给定力或位移时响应。
这项研究提出了一种具体的可复制方法，可用于研究适用于从活患者CBCT图像中提取的模型上的假想正畸力系统。在利用这种方法时，研究人员可以估计各种牙齿的CRES，并考虑牙齿结构的生物形态，如牙齿解剖学、根数及其在3D空间中的方向、质量分布和牙周附件的结构。此过程的概述如图1所示。这是为了将读者定向到用于定位CRES的3D齿模型生成所涉及的逻辑过程。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3-matic software</td>
			<td>Materialise, Leuven, Belgium.</td>
			<td></td>
			<td>Cleaning and meshing</td>
		</tr>
		<tr>
			<td>Abaqus/CAE software, version 2017</td>
			<td>Dassault Syst&#232;mes Simulia Corp., Johnston, RI, USA.</td>
			<td></td>
			<td>Finite Element Analysis</td>
		</tr>
		<tr>
			<td>Mimics software, version 17.0</td>
			<td>Materialise, Leuven, Belgium.</td>
			<td></td>
			<td>Segmentation of teeth and bone</td>
		</tr>
	</tbody>
</table>

a finite element approach for locating the center of resistance of maxillary teeth

电阻中心 （CRES） 被视为可预测牙齿运动的基本参考点。用于估计牙齿CRES的方法范围从传统的放射学和物理测量到模型或尸体标本的体外分析。涉及模型和单齿高剂量微CT扫描有限元分析的技术显示出很大的希望，但较新的、低剂量和低分辨率锥形束计算断层扫描（CBCT）图像却鲜有希望。此外，还描述了只有几颗精选牙齿（即最大中央切口、单体和首次摩尔）的CRES;其余的基本上被忽视了。还需要详细描述确定 CRES的方法，以便轻松复制和构建。
本研究使用常规的CBCT患者图像来开发工具和工作流程，以获得用于定位最大牙齿CRES的有限元模型。CBCT 体积图像纵，通过分割提取与确定最大牙齿的 CRES相关的三维（ 3D ）生物结构。通过 3matic 软件，对分段对象进行清理并转换为由四面体 （tet4） 三角形组成的虚拟网格，最大边缘长度为 1 mm。模型进一步转换为四面体实心体积网格，最大边缘长度为1 mm，用于有限元分析。工程软件 Abaqus 用于预处理模型以创建装配体并设置材料属性、交互条件、边界条件和负载应用程序。负载在分析时模拟系统上的应力和应变，有助于定位 CRES。这项研究是准确预测牙齿运动的第一步。

为了验证"程序"部分（步骤 2）中所述的分割和手动大纲，从干头骨中提取了最大第一摩尔，并拍摄了 CBCT 图像。图像处理和编辑软件 Mimics 用于手动概述齿，如步骤 2 所述。随后，进行了网格化，使用3matic软件对分段模型进行了清洗，并将其导入阿巴库进行分析。在牙齿的FE模型和实验室测量的实际牙齿（补充文件4）上进行的线性和体积测量中，我们没有发?...

Watch this Scientific Journal Video about A Finite Element Approach for Locating the Center of Resistance of Maxillary Teeth at JoVE.com

A Finite Element Approach for Locating the Center of Resistance of Maxillary Teeth

本研究概述了利用低剂量三维锥形束基于最大颌牙和颌牙的患者图像获得有限元素模型的必要工具。然后，这些患者模型用于准确定位所有最大牙齿的 CRES。

定位颌齿电阻中心的有限元方法

The center of resistance (CRES) is regarded as the fundamental reference point for predictable tooth movement. The methods used to estimate the CRES of ...

现在，这是第一次完成了一项工作，它提供了如何找出阻力中心的分步指南。这真的很重要，因为任何打算在此基础上进行的研究现在都不必回到绘图板，重新发明轮子，然后继续前进。并且它减轻了任何研究的巨大负担，这些研究打算在这个阻力中心概念上建立。这种分步方法将授权科学界以标准化的方式获得牙齿或一组牙齿质量中心的 3D 位置。该技术既可应用于最大尺寸，也可应用于毛化齿。将这个概念应用于具有多支架组件的类似复杂齿运动是很有趣的。对于牙齿和骨骼的分割，将锥形光束计算机断层扫描图像的原始 DICOM 文件加载到适当的医学成像软件程序中，并裁剪图像以仅包括感兴趣的牙齿和骨骼。右键单击"蒙版"选项卡，为图像创建新蒙版。单击"多切片编辑"工具，然后选择轴向、日冕或下垂视图。可按需要手动突出显示某些切片，然后选择"插值"工具以填充跳过切片的卷。然后单击"应用"，然后右键单击蒙版以生成齿形的 3D 音量。当为每个感兴趣的齿生成 3D 体积时，选择所有 3D 齿，然后右键单击以选择平滑。要分割骨骼，请右键单击蒙版选项卡，然后为图像创建新蒙版。要填充蒙版中可见的大孔，请单击"动态区域增长"工具。然后右键单击蒙版以生成骨骼的 3D 体积。要清理和网格化图像，请打开适当的数据优化软件程序，然后粘贴到选定的 3D 对象中。对于第一组的重复齿，单击"曲线模块"和"创建曲线"选项，然后手动绘制所有重复齿的水泥釉面结周围的曲线。从组 1 复制 3D 对象以生成组 2 的对象，并在"对象树"框中单击"对象"。从"曲面"列表中，删除第二组中每个对象的冠面，然后单击"设计模块"和"空心"以应用所需的参数。在第一组中，从"对象树"框中单击"对象"，并删除每个组的根曲面一个对象。选择"填充孔法线"选项，然后单击"添加轮廓和应用"。整个空间将被填满。选择"设计模块"和"局部偏移"，然后选择整个表冠曲面。选中"设计"和"偏移距离"和"缩小距离"选项，然后单击"应用"。在 Remesh 模块中，从对象树创建非歧管装配体、主实体和 Maxilla，并为每个对象选择相交实体。然后拆分非歧管组件。使用相交实体将非歧管程序集拆分两次，作为组 1 中的所有对象以及组 2 中的所有对象，并在每次拆分后单击"应用"。单击自适应网格并选择所有相交实体，然后单击"应用"。然后单击拆分非歧管组件。单击对象树中的组 2 中的"创建非歧管装配体、主实体和单个对象"，然后选择相交实体，然后选择与齿类型对应的"相应对象"。单击自适应网格并选择相交实体。然后单击"创建非歧管程序集"。要使用非歧管技术生成 0.2 毫米均匀的周周韧带宽度，必须遵循所演示的主实体和相交实体的相同顺序。当每颗齿都按演示进行处理后，单击"创建体积网格"并选择网格参数。在算盘中，单击"文件"和"运行脚本"，然后Model_setup_Part1.py。单击"模拟"、零件、Maxilla 和曲面。输入曲面名称和"选择曲面区域"，选择"按角度"并设置 15 作为角度。单击"模拟"和"零件"并选择 UL1 和曲面。命名曲面 UL1。在"选择曲面区域"下，选择"单独"，选择屏幕上的齿，然后单击"完成"。处理所有齿面后，单击"模型、模拟"和"零件"，然后UL1_PDL曲面。命名曲面UL1_PDL_Inner。在"选择曲面区域"下，选择"按角度"并输入 15 作为角度。选择UL1_PDL曲面并命名曲面UL1_PDL_Outer。在"选择曲面区域"下，选择"按角度"并设置 15 作为角度。处理所有周周韧带后，单击"文件"和"运行脚本"，然后Model_setup_Part2.py。单击"模拟"和"BC"。输入名称的 BC All，然后将步骤设置为初始。单击"模拟"、装配体、设置并命名U1_y_force。在上中央切口的扣面上选择表冠中心位置的节点，在"选择集合的节点"中，选择"单独"。然后单击"设置"和"创建集"，并在U1_z_force。若要设置模型，请单击"文件"和"运行脚本"，然后Model_setup_Part3.py。然后单击"文件"和"运行脚本"并选择Functions.py。要处理模型，请单击"文件"和"运行脚本"，然后Job_submission.py。在"全部禁止"对话框中，根据约束输入齿的两侧，然后单击"确定"。在"作业提交"对话框中，输入 Y 以运行指定齿或牙齿的分析，然后单击"确定"。然后，在"分析方向"对话框中，输入 Y 以指定强制应用，然后单击"确定"。要估计电阻中心，请选择"文件"、"运行脚本"和"Bulk_process.py。在"分析多个作业"对话框中，输入指定齿或齿的 Y，然后单击"确定"。在"分析方向"对话框中，为指定强制应用输入 Y，然后单击"确定"。在"获取输入"对话框中，输入指定实例中概述的特定齿号，然后单击"确定"。然后在"命令"框中选中"力关于点"和"估计位置"的坐标。为了验证所演示的分割和手动大纲，从干头骨中提取了最大第一摩尔，并拍摄了锥形光束计算机断层成像图像。然后执行网格化。观察了在实验室中测量的齿的有限元模型和实际齿的线性和体积测量无显著差异。为了验证用户定义的算法在确定物体电阻中心时的有效性，可以在脚本创建的初始阶段使用封装在护套中的光束的简化模型。通过遵循定义的算法及其计算，可以预测模型光束的电阻中心。在这里，可以观察到分配给结构的材料属性。牙周韧带和骨骼材料特性的建模差异会影响牙齿阻力中心的最终位置。为了标准化力向量并定位电阻中心的位置，可以按指示由 X、Y 和 Z 方向构造笛卡尔坐标系。每颗齿的 R 点定义为牙冠扣面上的几何中心，并选择用于近似操作员可能放置支架以施加正畸力的最近位置。在此代表性分析中，沿 Y 坐标和 Z 坐标应用力系统时沿 X 坐标获得的电阻中心位置不同，但平均差异较小。有限元分析对于新用户来说可能非常繁琐。执行预处理步骤的前几次，要有耐心和有条不紊。因此，这项研究是一项基础性研究。其一些应用可以预测牙齿运动，这对在校准器领域的公司来说非常至关重要。它可以用来找出许多牙齿的阻力中心，牙齿的片段，等等，在牙齿运动过程中产生的副作用，并且非常非常重要，也许在找出如何加速牙齿运动。

Research

Education

JoVE Core

JoVE Journal

Mechanical Engineering

Biology

Unit 1

Center of Gravity and Centroid

SCIENTISTS IN ACTION

Choice and No-Choice Assays for Testing the Resistance of A. thaliana to Chewing Insects

测试拟南芥耐咀嚼昆虫的选择和非选择性检测

Larvae of the small white cabbage butterfly are a pest in agricultural settings. This caterpillar species feeds from plants in the cabbage family, which ...

科研

生物学

Methods for the Study of the Zebrafish Maxillary Barbel

上颌Barbel斑马鱼的研究方法

Barbels are skin sensory appendages found in fishes, reptiles and amphibians.  The zebrafish, Danio rerio, develops two pairs of barbels- a short nasal ...

Bioassays for Monitoring Insecticide Resistance

生物测定对杀虫剂的抗药性监测

Pest resistance to pesticides is an increasing problem because pesticides are an integral part of high-yielding production agriculture. When few products ...

Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein

表达，洗涤剂溶解，和一个膜转运，MexB多药耐药蛋白的纯化

Multidrug resistance (MDR), the ability of a cancer cell or pathogen to be resistant to a wide range of structurally and functionally unrelated ...

Characterizing Herbivore Resistance Mechanisms: Spittlebugs on Brachiaria spp. as an Example

Characterizing Herbivore Resistance Mechanisms: Spittlebugs on Brachiaria spp. as an Example

表征草食动物的耐药机制：Spittlebugs臂形 SPP。为例

Plants can resist herbivore damage through three broad mechanisms: antixenosis, antibiosis and tolerance1. Antixenosis is the degree to which the plant is ...

Quantitative Comparison of cis-Regulatory Element (CRE) Activities in Transgenic Drosophila melanogaster

Quantitative Comparison of cis-Regulatory Element CRE Activities in Transgenic Drosophila melanogaster

定量比较顺调节元件（CRE）的活动，在转基因果蝇</em

Gene expression patterns are specified by cis-regulatory element (CRE) sequences, which are also called enhancers or cis-regulatory modules. A typical CRE ...

An Explant Assay for Assessing Cellular Behavior of the Cranial Mesenchyme

为外植体含量的颅间充质细胞行为评定

The central nervous system is derived from the neural plate that undergoes a series of complex morphogenetic movements resulting in formation of the ...

Assessing Murine Resistance Artery Function Using Pressure Myography

评估抗小鼠动脉功能使用压力Myography

Pressure myograph systems are  exquisitely useful in the functional assessment of small arteries, pressurized  to a suitable transmural pressure. The  ...

Isolation of Microvascular Endothelial Tubes from Mouse Resistance Arteries

从鼠标阻力动脉分离微血管内皮管

The control of blood flow by the resistance vasculature regulates the supply of oxygen and nutrients concomitant with the removal of metabolic ...

Autonomously Bioluminescent Mammalian Cells for Continuous and Real-time Monitoring of Cytotoxicity

自主的生物发光哺乳动物细胞连续和实时监测细胞毒性

Mammalian  cell-based in vitro assays have been  widely employed as alternatives to animal testing for toxicological studies but  have been limited due to ...