CAJ | 학술논문

背景:磨牙残冠修复时通常情况下残留的牙体较少,且修复后在各种受力情况下牙齿的应力分布能够直接影响修修复后效果,有限元法逐渐被应用到义齿的应力分析中.目的:建立带桩嵌体修复下颌第一磨牙残冠的三维有限元模型,为提高复杂牙齿的建模水平及分析修复方式的应力分布特点提供实验数据.设计:重复观察测量.单位:中山大学附属第一医院口腔科与放射科,华南理工大学交通学院固体力学系,光华口腔医学院修复科.材料:实验于2003-11/2004-12在华南理工大学交通学院应用力学系完成.选取离体的形态正常的人右下颌第一磨牙6颗,东芝Xpress/SX螺旋CT机,图像合成软件和有限元分析软件ANSYS.方法:从6颗离体的形态正常的人右下颌第一磨牙中,选取密合度最好且形态接近临床要求的1颗进行根管治疗,制作制锁式的带桩嵌体修复体.利用螺旋CT分别对修复前牙体、修复后戴入主根管的带桩嵌体的残冠、戴入二带桩制锁式嵌体的残冠进行断层扫描.通过图像合成软件建立残缺牙体、金属部分的三维数字模型,二者黏结形成修复后的整个牙体模型.为了更好的模拟天然牙在实际中的边界条件,将牙槽骨考虑在内.利用ANSYS软件中的Mesh命令,直接对模型进行智能网格划分.主要观察指标:修复前剩余牙体、修复后带桩嵌体、修复后的牙槽骨和牙体的三维有限元模型的建立与网格划分结果.结果:通过计算机建立了修复前剩余牙体、修复后带桩嵌体、牙槽骨和牙体的三维有限元模型,并进行网格自动划分,共有117 720个单元,20 988个节点,建成后的三维有限元模型与实体组织具有良好的几何相似性.结论:螺旋CT断层扫描技术与三维有限元法相结合,可以建立复杂的牙模型,且能真实地模拟实际情况,使用性好.
배경:마아잔관수복시통상정황하잔류적아체교소,차수복후재각충수력정황하아치적응력분포능구직접영향수수복후효과,유한원법축점피응용도의치적응력분석중.목적:건립대장감체수복하합제일마아잔관적삼유유한원모형,위제고복잡아치적건모수평급분석수복방식적응력분포특점제공실험수거.설계:중복관찰측량.단위:중산대학부속제일의원구강과여방사과,화남리공대학교통학원고체역학계,광화구강의학원수복과.재료:실험우2003-11/2004-12재화남리공대학교통학원응용역학계완성.선취리체적형태정상적인우하합제일마아6과,동지Xpress/SX라선CT궤,도상합성연건화유한원분석연건ANSYS.방법:종6과리체적형태정상적인우하합제일마아중,선취밀합도최호차형태접근림상요구적1과진행근관치료,제작제쇄식적대장감체수복체.이용라선CT분별대수복전아체、수복후대입주근관적대장감체적잔관、대입이대장제쇄식감체적잔관진행단층소묘.통과도상합성연건건립잔결아체、금속부분적삼유수자모형,이자점결형성수복후적정개아체모형.위료경호적모의천연아재실제중적변계조건,장아조골고필재내.이용ANSYS연건중적Mesh명령,직접대모형진행지능망격화분.주요관찰지표:수복전잉여아체、수복후대장감체、수복후적아조골화아체적삼유유한원모형적건립여망격화분결과.결과:통과계산궤건립료수복전잉여아체、수복후대장감체、아조골화아체적삼유유한원모형,병진행망격자동화분,공유117 720개단원,20 988개절점,건성후적삼유유한원모형여실체조직구유량호적궤하상사성.결론:라선CT단층소묘기술여삼유유한원법상결합,가이건립복잡적아모형,차능진실지모의실제정황,사용성호.
BACKGROUND:During the restoration of residual molar crown, a little part of tooth is still remained commonly. After the restoration, with various forces, stress distribution affects directly the results after restoration. Finite element method is gradually applied in stress analysis on artificial tooth.OBJECTIVE: To establish the three-dimensional (3-D) finite element model of post-inlay restoration of the first residual mandibular molar crown so as to provide experimental data for improving model establishment of complicated teeth and analysis on the property of stress distribution of restoring methods.DESIGN: Repeated observation and measurement were given.SETTING: Department of Stomatology and Department of Radiology of First Hospital affiliated to Sun Yat-sen University;Department of Solid Mechanics,College of Traffics and Communications, South China University of Technology; Department of Restoration of Guanghua College of Stomatology.MATERIALS: The experiment was performed in Department of Solid Mechanics, College of Traffics and Communications of South China University of Technology from November 2003 to December 2004. Six first mandibular molars on the right side with normal morphology in vitro were collected, and Toshiba Xpress/SX spiral CT machine, image photo synthesis software and finite element analysis software ANSYS were applied in the experiment.METHODS: 1 of the 6 first mandibular molars on the right side with normal morphology in vitro was selected for pulpectomy, which was the best in density and near to clinical requirement in morphology. With pulpectomy, the prosthesis of braking-lock post-inlay restoration was prepared. Spiral CT-cross scanning was performed in premolar crown before the restoration, the residual crown with post-inlay in main root canal after restoration and the residual crown with braking-lock second post-inlay restoration. With image photosynthesis software, 3-D digital model of residual tooth and metal part was established and the entire tooth model was prepared after adhesion of two parts. In order to provide better boundary conditions of simulated natural tooth in practice, alveolar bone was considered. Under Mesh order in ANSYS software, automatic mesh generation was performed in the model directly.MAIN OUTCOME MEASURES: Establishment of 3-D finite element models of residual tooth before restoration, post inlay, and alveolar bone and tooth after restoration and the results of mesh generation.RESULTS: By establishing 3-D finite element models of residual tooth before restoration, post inlay, alveolar bone and tooth after restoration and automatic mesh generation, there were altogether 117720 units and 20988nodes. Good geometric similarity presents between the construction model of 3-D finite element model and solid tissue.CONCLUSION: Combination of 3-D finite-element model with spiral Ctcross technology establishes complex dental models, simulates practical conditions authentically and is good in operation.