垫底材料厚度对髓腔固位冠修复后牙体组织应力影响的三维有限元分析  

Three-dimensional-finite-element Comparative Research of Different Cement Thickness in Endodontically Treated Mandibular Molar Restored with Endocrown Restorations

作　　者：张英[1] 熊璟[1] 李永强[1] 邱勇棋 庄瑞[1] 刘昶[1] 徐国庆 逯宜[3] ZHANG Ying;XIONG Jing;LI Yong-qiang;QIU Yong-qi;ZHUANG Rui;LIU Chang;XU Guo-qing;LU Yi(Department of Stomatology,Hanzhong Central Hospital,Hanzhong 723000, Shaanxi,China;Shenzhen Star Technology Service Co. LTD, Shenzhen 518000, Guangdong,China;Department of Prosthodontics,Stomatological Hospital,Xi’anJiaotong University Clinical Research Center of Shaanxi Province for Dental and Maxillofacial Disease,Xi’an 710004,Shaanxi,China)

机构地区：[1]汉中市中心医院口腔科,陕西汉中723000 [2]深圳市星空科技服务技术有限公司,广东深圳518000 [3]西安交通大学口腔医学院口腔修复科陕西省牙颌面疾病临床研究中心,陕西西安710004

出　　处：《中国美容医学》2019年第9期102-106,共5页Chinese Journal of Aesthetic Medicine

基　　金：陕西省重点研发项目(编号：2018SF-092);中华口腔医学会西部行口腔医学临床科研基金(编号：CSA-W017-01);陕西省牙颌疾病临床医学研究中心开放课题(编号：2018YHJB07)

摘　　要：目的:本研究通过锥形束CT(Cone beam computed tomography,CBCT)与Bluecam扫描技术,借助Geomagic和Solidworks 2012等逆向工程软件,建立下颌第一磨牙根管治疗后不同髓腔固位冠(Endocrown)修复材料以及不同垫底材料厚度的三维有限元模型,运用Ansys Workbenchl7.0软件分析Endocrown及剩余牙体组织应力大小和分布情况,为临床牙体缺损修复提供实验依据。方法:选择在修复科门诊完成下颌第一磨牙根管治疗的青年男性志愿者1名,完成右侧下颌第一磨牙根管治疗后行Endocrown修复,基牙预备后行CBCT扫描,利用CBCT扫描数据建立离体下颌第一磨牙三维有限元模型,模拟DO洞型并用Endocrown进行修复。选择三种不同修复材料(Emax CAD、LavaTM、ULtimate、金合金)根据VOCO树脂垫底的厚度不同分为1、3、5mm组,相应冠的厚度则分别为5、3、1mm。然后分别采用轴向和45°斜向静态加载模式对模型加载300N和112.5N的力,观察Endocrown和剩余牙体组织不同部位的应力分布情况,分析比较应力集中部位及相应部位应力峰值的差异。结果:垂直加载与舌向45°加载时,Von-mises应力和最大主应力均主要集中在Endocrown相应的加载部位;近远中颊髓线角、近远中舌髓线角、髓室底及根分叉等部位剩余的牙体组织Von-mises应力和最大主应力峰值均较低;牙颈部和洞型的远中肩台则出现应力集中趋势;垫底材料厚度为5mm时剩余牙体组织容易出现应力集中,尤其是缺损部位。结论:根管治疗后行Endocrown修复时,基牙颈部尤其是近缺损部位应力较为集中。所以保证颈周牙本质的完整,增强颈部的抗力,对于根管治疗后的患牙尤为重要。同种修复材料随垫底材料厚度的增加,剩余牙体组织更易引起应力集中;不同硬度和弹性模量的修复材料也会随垫底材料厚度的增加而更易形成应力集中。Objective An endodontically first mandibular molar was scanned by using computed tomography(CBCT)and Bluecam systerm.Three-dimensional finite-element model has been established and analyzed with soft wares on the regulations of the distribution of stress repaired of the DO cavity in endodontically first mandibular molar in order to provide some valuable advice for clinical practices.Methods The participate was chosen from the patients who attended the clinical research and sought denture therapy.The tooth was after preparation and then scanning by CBCT and Cerec Bluecam system to obtained 3 D dynamic images and designed endocrown.A finite element analysis model of mandibular first molar was using the scanning data acquired by CBCT. The distal-occlusio-cavity and endocrown restorations were simulated.The models were lined with three repairing material(Emax CAD, LavaTM Ultimate, gold alloy) and resin cement.Based on cement thickness of 1, 3 and 5 mm.A static axial and 45°loading 300 N and 112.5 N were respectively applied to each model.Threedimension finite element analysis was performed on the models under staticloads. Then, to compare stress among different models. Results The endocrown under vertical stress and oblique stress with 45 angles of every test groups on the Vonmises stress and maximum principal stress was situated the loading point. The vertical stress was obviously greater than the oblique stress with 45 angles. The remaining tooth after preparation under vertical stress and oblique stress with 45 angles of every test groups was situated the neck and the distal surface of Cavity. The most significant group was the LavaTM Ultimate group(under 5 mm). Conclusion When endocrown is used for the restoration of endodontically-treated molar.The stress on the neck was greater than others.For the endodontically-treated molar, protect the dentine and strengthen the resistance of tooth neck was very important.A thinner cement thickness has a better effect for the long term stabilization of abutment and the endo

关 键 词：三维有限元分析 髓腔固位冠 下颌第一磨牙 垫底厚度 应力分析 

分 类 号：R783.4[医药卫生—口腔医学]