可切削硅酸锂全瓷冠的力学差异性研究  

Research on the mechanical differences of machinable lithium disilicate all-ceramic crowns

作　　者：林晓敏[1] 徐远志[2] 杨启祥[2] 张东升[3] LIN Xiaomin XU Yuanzhi YANG Qixiang ZHANG Dongsheng(Shanghai Institute of Applied Mathematics and Mechanics, Shanghai 200072, P.R.China Department of Stomatology, The Tenth People＇s Hospital of Tongji University, Shanghai 200072, P.R.China Department of Mechanics, Shanghai University, Shanghai 200444, P.R.China)

机构地区：[1]上海市应用数学和力学所,上海200072 [2]同济大学附属第十人民医院口腔科,上海200072 [3]上海大学力学系,上海200444

出　　处：《生物医学工程学杂志》2017年第1期48-52,共5页Journal of Biomedical Engineering

基　　金：国家自然科学基金(11372173)

摘　　要：可切削硅酸锂陶瓷具有很好的色泽和较高的抗弯强度,它既可用于单层冠,也可以用作氧化锆基底冠的饰面瓷,再通过烧结或者粘接方式合成全瓷冠。本文研究了单层冠、烧结双层冠和粘接双层冠等3种结构形式的全瓷冠修复体在典型载荷作用下应力分布差异。建立了下颌第一磨牙单层冠、烧结双层冠和粘接双层冠等3种全瓷冠的三维数值模型,分别对其施加垂直集中载荷和八点均布载荷两种典型载荷,通过数值计算分析3种全瓷冠各部分的应力极值和应力分布。结果表明,3种瓷冠在两种载荷作用下的最大应力均小于材料的弯曲强度。烧结双层冠和粘接双层冠应力分布形式大体相同,与单层冠应力分布趋势不同。粘接双层冠与烧结双层冠相比,饰面瓷应力更大。在采用可切削硅酸锂陶瓷单层冠作为磨牙修复体时,在多次咀嚼载荷作用下高应力区可能导致全瓷冠的使用寿命缩短。与烧结双层冠相比,粘接双层冠的饰面瓷可能存在更大崩瓷的风险。本文结论可为可切削硅酸锂陶瓷材料在实际全瓷冠修复临床应用中提供参考意见。Due to the superior pigment and high flexural strength, machinable lithium disilicate ceramics can be used as a monolithic crown or veneering porcelains on the zirconia core to form the all-ceramic crowns by sintering or bonding procedures. This paper reports the research on the differences in stress distributions amongst these three types of all-ceramic crowns under typical loading conditions. Three-dimensional numerical models of the restored crown based on the first mandibular molar were developed. The vertical concentrated load and 8-point uniformly distributed load were applied, respectively. The maximum stress and stress distribution were resulted from finite element evaluation. It was found that the maximum tensile stress in 3 types of restored crowns subjected to the concentrate load was less than the flexural strength of IPS e.max. The stress distributions in the sintered and bonded double layered crowns were basically identical, and different from the monolithic crown. The stress magnitude in veneer porcelain of the bonded crown was greater than that in the sintered crown. The use of IPS e.max computer aided design monolithic crown as molar restorations should be careful to avoid high stress as the cyclic stress is a concern of fatigue which may influence the longevity of the restored crown. The bonded double layer crowns bear greater risks of veneer chipping compared with the sintered crowns. The conclusions of this study provide helpful guidelines in clinical applications for preparation of computer aided design/computer aided manufacture lithium disilicate all-ceramic restorations.

关 键 词：可切削硅酸锂 单层冠 粘接 有限元分析 应力 

分 类 号：R783.1[医药卫生—口腔医学]