不同洞径I类洞修复后牙体的应力分析

Numerical Analysis of the Anti-fracture Intensity of Packed and Repaired Tooth in Different Cavity Capacities

我们旨在研究不同洞径I类洞复合树脂修复后牙体的应力分布情况。采用CT扫描获取健康成人上颌牙的二维图像,通过计算机重建技术建立三维立体图像,并获得其有限元数据模型,在相同垂直载荷下对5种不同洞径I类洞修复前后的牙体应力状态进行数据分析。结果显示,在所设计的圆三角形I类洞受到50N相同作用力后,洞底切面直径从3.3 mm逐步长到3.7 mm时,其应力峰值依次为14.873、16.682、17.589、17.307和17.912MPa,各值间无明显差异,但应力峰值为正常牙的3倍。提示后牙树脂充填时,I类洞洞径的改变对牙体的应力峰值无显著影响,但牙体的承载能力较正常牙明显下降。

This study was aimed to assess the stress distribution of different capacity of class Ⅰ cavity after composite resin filling. A three -dimensional finite element made of the maxillary second molar was constructed by spiral CT scan technology. Based on this model, stress distribution in tooth was analyzed before and after post-core restorations with 5 different capacities of class Ⅰ cavity. When the circle triangle of class Ⅰ cavities being under 50N vertical pressures, the cavity capacity increased from 3.3 mm to 3.7 mm, the maximum tensile stress values of the composite resin restorations being 3 times those of normal tooth, which were 14. 872 MPa, 16. 682 MPa and 17. 589 MPa, 17. 307 MPa and17.912 MPa. Obviously, the effect of different capacities of class Ⅰ cavity on the maximum stress value enduring ability of teeth was samll, but in the analysis model, the enduring ability of teeth was reduced when the molars were filled with resin.