不同冠延长术式处理上中切牙冠根折并桩核冠修复的三维有限元比较  

Finite element analysis of the maxillary central incisor with traditional and modified crown lengthening surgery and post-core restoration in management of crown-root fracture

作　　者：甄敏[1] 危伊萍 胡文杰[1] 荣起国[2] 张豪[3] 

机构地区：[1]北京大学口腔医学院·口腔医院牙周科,100081 [2]北京大学工学院力学与工程科学系,100871 [3]北京大学口腔医学院·口腔医院修复科,100081

出　　处：《中华口腔医学杂志》2016年第6期362-367,共6页Chinese Journal of Stomatology

基　　金：北京市科学技术委员会首都临床特色应用研究基金（Z131107002213174）

摘　　要：目的 构建上中切牙不同冠根折类型行改良冠延长术后桩核冠修复的三维有限元模型,研究术后牙齿应力大小和分布情况,从力学角度对比分析常规和改良牙冠延长术的适应证.方法 采用显微CT扫描技术和三维激光扫描技术、DICOM数据直接建模法、逆向工程技术和有限元法,构建9种上中切牙冠根折类型行改良冠延长术后桩核冠修复的三维有限元模型（简称不同改良冠延长术模型）,分析牙体、牙周和修复体各结构（牙本质、牙周膜、牙槽骨、桩、核）的等效应力（von Mises stress）峰值及其分布位置、牙周膜面积、牙周膜极限阈值,并与本课题组既往研究中常规冠延长术模型的相关结果进行比较.结果 不同改良牙冠延长术模型中不同结构的等效应力大小：牙本质＞桩＞核＞牙槽骨＞牙周膜;牙本质的应力峰值（44.37～ 80.58 MPa）出现在舌侧中央肩台处;改良冠延长术术后牙周膜面积减少了6％～28％,在相同折裂条件下,改良冠延长术模型保留的牙周膜面积大于常规冠延长术模型;改良冠延长术模型中仅B3L1m、B3L2m、B3L3m模型的牙周膜应力超过了牙周膜的极限阈值,而常规冠延长术模型中的B2L2c、B2L3c、B3Llc、B3L2c、B3L3c模型的牙周膜应力均超过了牙周膜的极限阈值.结论 改良冠延长术较常规法保留了相对多的牙周支持组织,有利于术牙的远期疗效;改良冠延长术的适应证范围大于常规冠延长术;唇侧折裂平齐龈缘且舌侧折裂至牙槽嵴顶及其根方的上前牙冠根折不是改良冠延长术的适应证.Objective To construct three-dimensional finite element models with modified crown lengthening surgery and post-core restoration in management of various crown-root fracture types,to investigate the intensity and distribution of stressin models mentioned above,and to compare and analyze the indications of traditional and modified crown lengthening surgeries from the mechanic point of view.Methods Nine three-dimensional finite element models with modified crown lengthening surgery and post-core restoration were established and analyzed by micro-CT scanning technique,dental impression scanner,Mimics 10.0,Geomagic studio 9.0 and ANSYS 14.0 software.The von Mises stress of dentin,periodontal ligament,alveolar bone,post and core,as well as the periodontal ligament area and threshold limit value were calculated and compared with the findings of traditional crown lengthening models which had been published earlierby our research group.Results The yon Mises stress intensity of modified crown lengthening models were：dentin＞post＞core＞alveolar bone＞periodontal ligament.The maximum von Mises stress of dentin（44.37-80.58 MPa） distributed in lingual central shoulder.The periodontal ligament area of the modified crown lengthening surgery was reduced by 6％ to 28％,under the same crown-root fracture conditions,the periodontal ligament area of modified crown lengthening models was larger than that of the traditional crown lengthening models.In modified crown lengthening surgery models,the yon Mises stress of periodontal ligament of B3L1m,B3L2m,B3L3m models exceeded their limit values,however,the yon Mises stress of periodontal ligament of the B2L2c,B2L3c,B3L1c,B3L2c,B3L3c models exceeded their limit values in traditional crown lengthening surgery models.Conclusions The modified crown lengthening surgery conserves more periodontal supporting tissues,which facilitates the long-term survival of teeth.The indication of modified crown lengthening surgery is wider than traditional method.The maxillary central incisors w

关 键 词：牙折断 牙冠伸长术 有限元分析 牙冠 牙根 

分 类 号：R783.3[医药卫生—口腔医学]