下颌第一磨牙Ⅱ类洞与隧道洞的有限元应力比较

TDF analysis of stress between tunnel and Class Ⅱ cavity of mandibular first molar

目的建立下颌第一磨牙的三维有限元模型,研究Ⅱ类洞型与隧道洞型的应力。方法利用牙CT机获得带三维坐标的断层数据及图像,利用Pro/Engineer软件转换数据,采用Ansa软件划分网格,运用Ansys 9.0软件建立下颌第一磨牙的三维有限元模型。在模型上分别制备Ⅱ类洞型与隧道洞型。分别模仿咬力垂直及斜向加压,利用Ansys软件分析比较牙体变形及所受应力情况。结果无论牙体变形量、所受应力大小、应力分布的均匀度,均支持后牙作隧道洞型比Ⅱ类洞型更能保持牙体的牢固度。结论后牙邻面洞制备成隧道洞型较之Ⅱ类洞型更能保持牙体的牢固度。

Objective To build a TDF model of the mandibular first molar , then study the stress on tunnel cavity and on Class Ⅱ cavity when the pressure is exerted. Methods The fracture data and pictures of three finite dements were got with the tooth CT machine. The data of the teeth were transformed with Pro/Engineer software. Then the mandibular first molar＇ s three finite elements model was built by Ansa and Ansys software. On the model, the cavities were prepared. Vertical pressure and inclined pressure were exerted on the models,imitating true teeth occlusive pressures. The deformation and stress of the teeth were analysed and compared with Ansys software. Results Including the deformation, the stress and the distribution of stress all supported that it would be more strengthened when the tooth was prepared into tunnel cavity than into Class Ⅱ cavity. Conclusion The tooth will be timer when it is prepared into tunnel cavity than into Class Ⅱ cavity.