无托槽隐形矫治器压低上颌伸长第一磨牙的有限元分析  

Finite element analysis on overerupted maxillary first molar intrusion using clear aligner

作　　者：王碧琦 张苗苗[2] Wang Biqi;Zhang Miaomiao(Harbin Medical University,Harbin 150000,Heilongjiang Province,China;Department of Orthodontics,First Affiliated Hospital of Harbin Medical University,Harbin 150000,Heilongjiang Province,China)

机构地区：[1]哈尔滨医科大学,黑龙江省哈尔滨市150000 [2]哈尔滨医科大学附属第一医院口腔正畸科,黑龙江省哈尔滨市150000

出　　处：《中国组织工程研究》2023年第25期4051-4056,共6页Chinese Journal of Tissue Engineering Research

摘　　要：背景:对于骨质密度不同的成年患者,在运用隐形矫治器压低上颌伸长磨牙时,正畸医师多由主观经验选择膜片厚度,有限元分析有望为不同骨质密度患者选择合适厚度的膜片提供理论依据。目的:通过有限元法分析膜片厚度及骨质密度对成年患者运用隐形矫治技术压低上颌伸长磨牙的影响。方法:基于4种骨密度类型(骨松质Ⅰ类、Ⅱ类、Ⅲ类、Ⅳ类)建立4组有限元模型,并分别与膜片厚度为0.5,0.75,1 mm的3种隐形矫治器模型进行组装,运用Ansys 2021软件进行有限元分析,各组模拟隐形矫治器对上颌第一磨牙施加0.2 mm压低位移,比较各组第一磨牙及其邻牙牙根、牙周膜、牙槽骨的等效应力与牙体位移趋势。结果与结论:①各组第一磨牙的等效应力分布情况相同,主要分布于根分叉处;第二前磨牙的等效应力分布于近中颈1/3;第二磨牙的等效应力分布于两颊根根分叉处。②第一磨牙及邻牙均产生近中、压低位移趋势;第一磨牙产生颊侧位移趋势,邻牙产生腭侧位移趋势。Ⅱ类骨密度下,第一磨牙X、Y轴位移量最小,Z轴位移量最大;邻牙位移量随骨密度降低而增加。Z轴方向上,第一磨牙及邻牙位移量与膜片厚度呈正比;X、Y轴方向上,第二前磨牙膜片厚度1 mm组位移量最小,第二磨牙膜片厚度0.5 mm组最小。③结果显示,运用无托槽隐形矫治器压低伸长磨牙不易造成牙周膜变性及牙根吸收;骨质密度降低不会增加牙根吸收风险,Ⅱ类骨质密度最适宜作伸长磨牙压低移动;牙周膜、牙槽骨最大等效应力与膜片厚度呈正比。BACKGROUND:Intrusion of overerupted posterior teeth with clear aligner for adult patients with different bone densities,orthodontists mostly choose the diaphragm thickness by subjective experience,and finite element analysis is expected to provide a theoretical basis for choosing the appropriate thickness of diaphragms for patients with different bone densities.OBJECTIVE:To analyze the effects of diaphragm thickness and bone density on the intrusion of ove rerupted maxillary first molar in adult patients using clear aligners using finite element analysis.METHODS:Four groups of finite element models were created based on four bone densities(cancellous bone typesⅠ,Ⅱ,Ⅲ,andⅣ)and assembled with three clear aligner models with diaphragm thicknesses of 0.5,0.75,and 1 mm,respectively.Finite element analysis was then performed using Ansys 2021 software.Clear aligners applied a 0.2 mm intrusion displacement to the maxilla ry first molar was simulated in each group.The von Mises stress and tooth dis placement trends of root,pe riodontal ligament,alveolar bone of first molar and its adja cent teeth were compared between groups.RESULTS AND CONCLUSION:(1)The von Mises stress distribution of the first molar was the same in all groups,mainly at the root furcation;the second premolar was distributed in the proximal mid-cervical 1/3;the second molar was distributed at the buccal root furcation.(2)The displacement of the first molar and adja cent teeth was close to mesial displacement;the first molar displayed a buccal displacement trend,whereas adja cent teeth displayed a palatal dis placement trend.At classⅡdensity of alveolar bone,the first molar X-and Y-axis displacement was the smallest,and the Z-axis displacement was the greatest;displacement of adjacent teeth increased with decreasing bone density.In the Z-axis direction,the displacement of the first molar and adjacent teeth was proportional to the thickness of the diaphragm.The smallest displacement was observed in the second premolar 1 mm and second molar 0.5 mm

关 键 词：无托槽隐形矫治器 压低磨牙 膜片厚度 骨质密度 等效应力 有限元分析 

分 类 号：R459.9[医药卫生—治疗学] R318[医药卫生—临床医学] R783.5