冠外精密附着体用于下颌单侧游离端缺失的三维有限元应力分析

我们考虑基托与缺牙区牙槽嵴之间的接触,建立了冠外精密附着体用于单侧游离端缺失时的完整牙槽骨和全牙列三维非线性有限元模型,分析了牙周组织未吸收时基牙数目不同和牙周组织不同程度吸收时,第二前磨牙牙体及其牙周组织的应力情况。结果表明,牙周组织未吸收时增加基牙数目可以降低牙体及牙周组织的应力,使用两颗基牙较一颗基牙相比应力明显降低,而使用三颗基牙与两颗基牙相比应力变化不明显。结果提示,临床中宜使用两颗基牙进行修复。牙周组织吸收时,牙周组织应力随吸收程度的增大而增大,而牙体应力相对牙周组织应力变化小。当牙周组织吸收牙根长度的1/2时增加第三颗基牙,可以有效降低牙周组织的应力,临床中仍可使用冠外精密附着体进行修复。

Three-dimensional Finite Element Stress Analysis of Mandibular Unilateral Distal-extension with Extracoronal Precision Attachment

From alveolar bone and the complete dentition CT images, a three-dimensional nonlinear finite element model of mandibular unilateral distal-extension with extracoronal precision attachment was established.The contact elements were used between the denture and alveolar bone.The result shows that,the stress in the second premolar and periodontal tissue decreased obviously as the second abutment was added.However,the stress difference was unapparent as the third abutment was added.Considering various facts,the attachment with two abutments was suggested to be used.With the decrease of the periodontal tissue,the stress in the periodontal tissue increased,however the stress in the tooth changed slightly.The stress in the periodontal tissue decreased effectively when the third abutment was added,as the tooth root was absorbed by 50%.In this situation,the extracoronal precision attachment can also be used.