下颌第一磨牙缺失后第二磨牙牙周应力分布的三维有限元研究

Stress Distribution in the Dental Surrounding Tissues of the Second Mandibular Molar with the First Mandibular Molar Loss: a Three-dimensional Finite Element Analysis

【目的】探讨下颌第一磨牙缺失后下颌第二磨牙牙周支持组织中的应力分布。【方法】采用薄层CT扫描技术和Ansys有限元软件建立下颌第一磨牙缺失前后下颌第二磨牙的三维有限元固定桥修复模型,施加载荷计算并分析牙周应力分布状况。【结果】下颌第一磨牙缺失后下颌第二磨牙近远中牙槽嵴顶和根尖处应力较缺失前增加,发生了应力集中的现象。【结论】下颌第一磨牙缺失后下颌第二磨牙牙周组织的应力改变会导致下颌第二磨牙的近中倾斜,并产生进一步的牙体、牙周甚至整个牙颌系统的损伤。

[Objective] To evaluate the stress distribution in the surrounding tissues of the second mandibular molar with the first mandibular molar loss using a finite element analysis. [Methods] Two three-dimensional finite element models of the second mandibular molar with or without the first mandibular molar were constructed by the combination of the Computed Tomographic （CT） scanning technology and Ansys software. A vertical load of 22.5 kg was applied to the second molar on the central fossae in each case. The stress distribution in the surrounding tissues of the second mandibular molar was compared. [Results] The first mandibular molar loss increased the stress in the mesial , distal alveolar ridge and the apex of the second mandibular molar and increased the stress surrounding the second mandibular molar, [Conclusion] The stress distribution around the roots of the second mandibular molar with the first mandibular molar loss may tilt the second mandibular molar mesially and do harm to the tooth, paradontal tissues and the orofacial system.