Modeling the Mechanical Behavior of the Periodontal Ligament in Response to Externally Applied Loading

2012年，加拿大健康信息研究所(Canada Institute For Health Information)估计，加拿大人在牙科保健上的花费超过110亿美元，预计这个数字还会上升。牙周膜(PDL)是连接牙齿和周围牙槽骨的结缔组织，是牙科最重要的领域之一。在正畸治疗中，牙周膜在支持牙齿、分配外力和促进牙齿移动方面起着至关重要的作用。因此，对牙周膜对外加载荷的反应有一个完整的了解对于牙科领域是至关重要的。本项目的目的是研究PDL的粘弹性行为，并进一步了解它如何影响牙齿-PDL-骨复合体(TPBC)中的载荷分布。*将采用实验和力学建模相结合的方法研究PDL力学。将对分离的PDL组织进行蠕变-应变和应力-松弛实验，这些实验数据将用于建立和验证两种加载模式下的非线性粘弹性力学模型。相关方法也将被用来探索蠕变-应变模型系数与应力松弛模型系数之间的关系。采用有限元分析(FEA)的方法对完整的TPBC的力学性能进行了研究。我们研究中开发的粘弹性模型将被合并到PDL组织的预测有限元模型中。此外，光纤应变测量技术将用于在完整的TPBC实验中收集来自PDL的体外数据，以开发和验证FEA模型；这一点在文献中尚未实现。一名博士、两名硕士和每年至少一名本科生将在整个项目中接受培训。*建议的项目包括建模和实验流，并形成一套全面的方法来研究PDL对外加载荷的响应。这项研究对了解牙齿和周围骨之间通过牙周膜的载荷转移有直接的意义。这些信息对于普通牙医、修复牙医(例如种植机械师)和正畸医生来说是至关重要的。从长远来看，这项研究将为牙科护理接受者改进种植和正畸用具的设计和开发。此外，本程序中使用的方法还将应用于对非线性粘弹性材料感兴趣的其他研究领域。这种材料将包括聚合物复合材料或其他生物组织(例如肌腱或韧带)。

In 2012, the Canadian Institute for Health Information estimated that over $11 billion dollars was spent by Canadians on dental care, with this number projected to rise. One primary area of importance to dentistry is the periodontal ligament (PDL), connective tissue joining the tooth to the surrounding alveolar bone. The PDL plays a critical role in tooth support, distributing applied loads, and facilitating tooth movement during orthodontic treatment. As a result, having a complete understanding of PDL response to applied loading is vital to the field of dentistry. The objective of this program is to investigate the viscoelastic behavior of the PDL and further our understanding of how it effects load distribution in the tooth-PDL-bone complex (TPBC).******A combination of experimental and mechanical modeling approaches will be utilized in the study of PDL mechanics. Creep-strain and stress-relaxation experiments will be conducted for isolated PDL tissue, and this experimental data will be used to develop and validate nonlinear viscoelastic mechanical models in both loading modalities. Interrelation methods will also be used to explore relating model coefficients in creep-strain to those in stress-relaxation, and vice versa. Finite element analysis (FEA) methods will be employed to study the mechanics of the complete TPBC. Viscoelastic models developed in our research will be incorporated into the predictive FEA model for PDL tissue. In addition, fibre optic strain measurement techniques will be used to gather ex vivo data from the PDL in complete TPBC experiments towards FEA model development and validation; something that has yet to be achieved in the literature. One PhD, two MSc, and at least one undergraduate student per year will be trained throughout this program.******The proposed projects include modeling and experimental streams, and form a well-rounded methodology to investigate PDL response to applied loading. This research has direct implications towards understanding load transfer between a tooth and surrounding bone through the PDL. Such information is vital to general dentists, restorative dentists (e.g. implant mechanics), and orthodontists. In the long-term, this research will lead to improved implant and orthodontic appliance design and development for dental care recipients. Furthermore, the methods used in this program will have applications in other areas of research where nonlinear viscoelastic materials are of interest. Such materials would include polymer composites or other biological tissues (e.g. tendons or ligaments).