双根管桩核冠的三维有限元分析

A study of stress distribution in twin-root canal with dowel-core crown by three dimension finite element method

目的用三维有限元法研究3种不同桩核材料修复双根管桩核冠前后牙本质中的应力分布,为临床双根管桩核冠选择合适的桩核材料提供理论依据。方法采用螺旋CT扫描数据建立上颌第一双尖牙的三维实体有限元模型,在此基础上,就平行于牙体长轴加载工况,对铸造Ni-Cr合金、铸造钛合金、聚乙烯纤维树脂3种材料进行了桩核修复前后的牙本质应力分布情况进行分析。结果与桩修复前相比,铸造Ni-Cr合金桩修复后桩尖周围牙本质的最大主应力和Von Mises应力峰值分别增大了66.5%和57.1%;而采用聚乙烯纤维树脂桩修复后,牙本质中的应力分布与修复前相比改变很小。铸造钛合金桩修复前后,牙本质中的应力状况改变较为显著。结论影响桩植入前后的牙本质中应力变化最显著的因素是桩材的弹性模量。与牙本质弹性模量相近的材料如聚乙烯纤维树脂,适合用于桩的修复。

Objective To investigate stress distribution of different material restored post-cores in dentin of twin-root canal PFM crown and provide a theoretical guidance for clinical use. Methods By SCT scanning, a three dimensional finite element model of maxillary first premolar restored with post-core and PFM crown was constructed. Based on this model, stress distribution in dentin was analyzed before and ＇after post-core restorations with 3 different materials, including cast Ni-Cr alloy, cast titanium alloy, and polythene fiber reinibrced composite. Results When the tooth was restored with cast Ni-Cr alloy, the maximum tensile stressand and Von Mises stress in dentin at post apex increased 66.5 %, 57.1%, respectively , polythene fiber reinforced composite as post materials , the stress distribution did not significantly change. The other material, stress distribution changed greatly. Conclusion The elastic modulus of post-core materials affected the stress distribution pattern in dentin. The materials with elastic modulus similar to that of dentin, such as polythene fiber reinforced composite, may be suitable for post restoration.