Background: The function of periodontal ligament (PDL)-cementum enthesis (PCE) in transferring the mechanical stimuli within the tooth–periodontium (PDT)–bone complex was not made clear yet. This study aimed to evaluate the effects of PCE on the mechanical stimuli distribution within the PDL and alveolar bone in the tooth–PDT–bone complex under occlusal forces using the finite element method. Methods: A computed tomography-based model of alveolar bone and second premolar of mandible was constructed, in which the PDT was considered at the interface of alveolar bone and tooth. Under a 3 MPa distributed occluso-apical masticatory load, applied over the uppermost surface of crown, the von Mises strain (vMST) and strain energy density (SED) within PDL, and von Mises stress (vMSR) and SED within alveolar bone were calculated in two situations: 1. When the PCE was absent; and 2. When the PCE was present between the PDL and cementum. Results: PCE levels-off SED and vMST within PDL up to 59% and 27%, respectively, compared to the model with no PCE. Moreover, in the alveolar bone, SEDs and vMSR increased up to 28% and 30%, respectively, compared to the model without PCE. Conclusion: By including PCE in the tooth–PDT–bone model, the mechanical stimuli shifted from PDL to its surrounding alveolar bone. Thus, it can be speculated that the tooth–PDT–bone complex has the capability of reducing the risk of PDL damage, through shifting excess mechanical stimuli from PDL toward the alveolar bone, during prolonged cyclic masticatory loading, as well as while one applies nonphysiologic and therapeutic loads, such as in orthodontic tooth movement.

中文翻译：

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PDL-水泥基在咀嚼负荷下保护 PDL 中的作用：有限元研究

背景：牙周韧带（PDL）-牙骨质（PCE）在牙-牙周（PDT）-骨复合体中传递机械刺激的功能尚不清楚。本研究旨在使用有限元方法评估在咬合力作用下，PCE 对牙齿-PDT-骨复合体中 PDL 和牙槽骨内机械刺激分布的影响。 方法：构建了基于计算机断层扫描的牙槽骨和下颌第二前磨牙模型，其中PDT被考虑在牙槽骨和牙齿的界面处。在 3 MPa 分布的咬合根尖咀嚼负荷下，施加在牙冠的最上表面，计算 PDL 内的 von Mises 应变 (vMST) 和应变能密度 (SED)，以及牙槽骨内的 von Mises 应力 (vMSR) 和 SED在两种情况下： 1. PCE 不在时；和 2. 当 PDL 和牙骨质之间存在 PCE 时。 结果：与没有 PCE 的模型相比，PCE 将 PDL 内的 SED 和 vMST 分别降低了 59% 和 27%。此外，与没有 PCE 的模型相比，在牙槽骨中，SED 和 vMSR 分别增加了 28% 和 30%。 结论：通过在牙齿-PDT-骨模型中加入 PCE，机械刺激从 PDL 转移到其周围的牙槽骨。因此，可以推测，牙齿-PDT-骨复合物具有降低 PDL 损伤风险的能力，通过将多余的机械刺激从 PDL 转移到牙槽骨，在长时间的循环咀嚼负荷期间，以及在应用非生理性负荷时和治疗负荷，例如正畸牙齿移动。