垫底材料及厚度对下颌第二乳磨牙嵌体修复应力分布影响的三维有限元分析  

Three-dimensional Finite Element Analysis of the Influence of Base Materials and Thickness on Stress Distribution of Mandibular Second Deciduous Molar Restored with Inlay.

作　　者：蔡长宇 冯娜 杨玉娥 CAI Changyu;FENG Na;YANG Yu'e(Department of Pediatric Dentistry, Qingdao Stomatological Hospital, Qingdao 266001, China.)

机构地区：[1]青岛市口腔医院儿童口腔科,山东青岛266001

出　　处：《口腔医学研究》2022年第7期654-658,共5页Journal of Oral Science Research

基　　金：青岛市医疗卫生重点学科建设项目(编号:2020-2022)。

摘　　要：目的:建立经根管治疗后的下颌第二乳磨牙嵌体修复三维有限元模型,分析髓室底垫底材料及厚度变化对应力分布的影响。方法:利用CBCT扫描建立下颌第二乳磨牙近中临牙合面缺损的三维有限元模型,模拟树脂嵌体进行修复。实验组选用3种弹性模量依次增加的材料(光固化玻璃离子、流动树脂、高强度玻璃离子)及3种不同厚度(0.5 mm、1.0 mm和1.5 mm)进行垫底,对照组为无垫底。采用轴向和侧向(45°)分别加载100 N的力,观察牙体组织及嵌体的应力分布情况,比较应力集中部位及峰值应力的变化。结果:(1)应力集中部位:轴向及侧向加载时,实验组及对照组应力集中部位相似,牙体组织的应力主要集中于下颌第二乳磨牙的牙颈部,近中偏舌侧最大,嵌体的应力主要集中于牙合面和近中。(2)峰值应力变化:轴向及侧向加载时,牙体组织的峰值应力均随着垫底厚度及垫底材料弹性模量增加而减小,而嵌体的峰值应力随着垫底厚度增加呈现先减小后增大的趋势,此外弹性模量增加时,嵌体峰值应力在轴向加载时变化不明显,侧向加载时垫底材料弹性模量增加峰值应力减小。结论:使用高弹性模量的垫底材料进行适宜厚度的垫底,有利于缓解根管治疗后下颌第二乳磨牙牙体组织及树脂嵌体的应力集中。Objective:To analyze the influence of base material and its thickness on stress distribution of the mandibular second deciduous molar which repaired with inlay after root canal treatment by three-dimensional finite element analysis.Methods:A three-dimensional finite element model of mandibular second deciduous molar with mesial and occlusal defects was established by CBCT scanning,and the resin inlay was simulated for restoration.The experimental group selected three kinds of materials with increasing elastic modulus(light cure glass ionomer,flowable composite resin,and high strength glass ionomer)and three kinds of thicknesses(0.5 mm,1.0 mm,and 1.5 mm)as the base.The control group was without base.By loading a force of 100 N in the axial and lateral directions(45°)respectively,the stress distribution of tooth and inlay was observed,and the stress concentration positions and the change of peak stress were compared.Results:When axial and lateral forces were loaded,(1)stress concentration position:the stress concentration positions of experimental group and control group were similar,the stress of the mandibular second deciduous molar was mainly concentrated on the neck with the largest in the mesial and lingual,and the stress of the inlay was mainly concentrated on the occlusal and mesial;(2)peak stress change:the peak stress of the tooth was decreased when the thickness and elastic modulus of the base material were increased.However,the peak stress of the inlay was firstly decreased and then increased with the increase of the thickness of base material.And the peak stress of inlay did not change significantly under axial loading but decreased under lateral loading with the increase of elastic modulus.Conclusion:Base material with high elastic modulus and suitable thickness is beneficial to alleviate the stress concentration of mandibular second deciduous molar and the resin inlay after root canal treatment.

关 键 词：垫底材料 垫底厚度 下颌第二乳磨牙 三维有限元分析 

分 类 号：R783.1[医药卫生—口腔医学]