目的

研究两种附着体义齿（栓道附着体义齿和套筒冠固定义齿）修复下颌第一磨牙缺失伴下颌第二磨牙近中倾斜30°的基牙的牙周组织应力分布。

方法

在已经建立的下颌第一磨牙缺失伴下颌第二磨牙近中倾斜30°修复前及两种附着体义齿修复后的三维有限元模型上，将200 N 垂直负荷和斜向负荷分别模拟加载于下颌第二磨牙，计算分析基牙牙周组织的应力情况。

结果

在下颌第二磨牙近中倾斜30°时，两种附着体义齿修复后倾斜基牙应力主要集中在其颈部牙槽骨或根分叉区。 斜向加载下，栓道附着体义齿修复后倾斜基牙牙周组织应力小于套筒冠义齿修复。 斜向加载下，下颌第二前磨牙和第二磨牙牙周组织应力远远大于垂直加载。

结论

在下颌第二磨牙近中倾斜30°时，栓道附着体义齿修复在改善倾斜基牙牙周组织应力方面更优于套筒冠义齿修复。 斜向加载时，下颌第二前磨牙和第二磨牙牙周组织中产生较大的应力集中。

Objective

To compare the abutment's periodontal stress distribution of two types of attachment-retained denture （key-keyway attachment denture and telescopic crown denture） used in the case of missing mandibular first molar and 30° mesial tilted second molar.

Methods

Based on the three-dimensional finite element models of missing mandibular first molar and 30° mesial tilted second molar with or without attachment denture restoration， 200 N vertical and oblique loads were applied respectively to the second molar to simulate a posterior contact.The stresses in the surrounding tissues of the mandibular second premolar and the second molar were compared.

Results

After restored with the two types of attachment dentures， stress mainly concentrated around the cervix of the alveolar bone or the root-furcation area of the tilted abutment. Under oblique load， the stress values of the alveolar bone of the tilted abutment with key-keyway attachment was smaller than that with telescopic crown. The stress values of the mandibular second premolar and the second molar under oblique load were significantly larger than those under vertical load.

Conclusions

Key-keyway attachment denture is better than telescopic crown denture in ameliorating the stress distribution in the periodontal tissue of 30°tilted abutment. Oblique load produces larger stress concentration in periodontal tissue of mandibular second premolar and second molar in comparison with vertical load.