摘要
目的:采用二维有限元法,比较在功能状况下,上颌中切牙3种不同直径一体化计算机辅助设计与制作(computer aided design and computer aided manufacturing,CAD/CAM)的氧化锆全瓷桩核修复后,桩核及牙根的应力分布情况,为CAD/CAM一体化全瓷桩核的临床合理应用提供指导。方法:用上颌中切牙分别建立直径1.5 mm、2.0 mm、2.5 mm的一体化CAD/CAM氧化锆全瓷桩核修复后的二维有限元模型,基牙分为无肩领和2.0 mm高肩领两组,共6种模型。用100 N力,通过牙长轴与切缘垂直向加载和切缘下腭侧2.0 mm与牙体长轴45°角斜向加载,模拟上、下切牙相对时和下颌前伸运动时的两种受力情况。结果:在100 N垂直向加载下,直径为2.0 mm的一体化CAD/CAM氧化锆全瓷桩核的应力分布更加均匀,牙根的应力集中区位于桩末端的根管内侧壁,其力值随着桩直径的增大而增大;在100 N 45°角斜向加载下,所有一体化CAD/CAM氧化锆全瓷桩核和牙根的最大应力值是垂直向加载下的3倍以上,桩核的最大应力位于根管内桩的唇侧中1/3,应力集中不明显,牙根的应力集中区位于桩末端的外侧壁及根尖孔区。在2.0 mm肩领存在时,相同直径的桩核和牙根的最大应力较无肩领设计时减小。结论:在一体化CAD/CAM氧化锆全瓷桩核根管预备时2.0 mm的直径有利于应力的均匀分布,末端牙体预备要防止应力集中,前伸侧向力对牙根及桩核的影响较大,根尖1/3是可能发生根折的部位。
Objective： To compare the stress distribution of teeth restored with one-piece of computer aided design and computer aided manufacturing（CAD/CAM） zirconia post-cores in three different radiuses.Methods： Constructing the 2D finite element models of the standard maxillary central incisal restored by one-piece of CAD/CAM zirconia post-cores and all ceramic crowns,the radius of post was 1.5 mm,2.0 mm and 2.5 mm respectively.Two tooth root types with or without the ferrule were constructed and there were 6 models in general.Group 1： 100 N force loading to the restored teeth through the long axle of teeth and veritical the incisal edge.Group 2： 100 N inclined force loading beneath the incisal edge 2.0 mm by 45° cross the long axle of teeth in the palate side.The stress distribution characteristic of post-cores and teeth roots were analysed.Results： In veritical loading,the stress distribution of one-piece of CAD/CAM zirconia post-core with 2.0 mm radius was better distributed than the two others,The stress concentration of teeth roots locate at the root canal wall where the end of the post exists,which increased with the wider radius of the post-core.In 45° inclined loading,the maximum stress of the zirconia post-core and the teeth root was more than three times of which in vertical loading.In post-cores,the stress concentration was in the labia middle 1/3 of the post.In teeth roots,the stress concentration located at the lateral wall in the post end and the area of the apical foramen.The stress of the post-cores and teeth roots was decreasing in the teeth root with a 2.0 mm ferrule.Conclusion： 2.0 mm radicus of the one-piece of CAD/CAM zirconia post-core is a better choice in clinic.There should be a conical degree in the teeth roots preparing for one-piece of CAD/CAM zirconia post-core restoration.The force of protrusive movement has a greater influence on the post-core and teeth roots.The area of apical may be apt to break in overloading.
出处
《北京大学学报（医学版）》
CAS
CSCD
北大核心
2012年第1期93-97,共5页
Journal of Peking University:Health Sciences
关键词
有限元分析
计算机辅助设计
牙修复体设计
桩核技术
氧化锆
Finite element analysis
Computer aided design
Dental prosthesis design
Post and core technique
Zirconia
