前牙区平台转换种植体不同种植深度的生物力学分析

The biomechanical analysis on platform switching implants with different planting depth in front maxilla

目的采用三维有限元方法建立平台转换种植系统的模型,分析平台转换种植系统应用于前牙时,不同加载时种植体植入不同深度的应力分布情况。方法利用Solidwork2007设计软件和Ansys Workbench有限元分析软件,分析平台转换种植体分别在植入牙槽嵴水平、牙槽嵴下1 mm(minus1)、牙槽嵴下2 mm(minus2)时的应力分布情况,以常规种植体为对照组。结果平台转换种植体中牙槽嵴顶骨质的应力值随种植体植入深度加深而有效降低,且比常规组小,而常规组随种植体深入种植应力没有发生明显变化。垂直加载下,各个模型中平台转换基台的应力分布基本相似,与种植深度无明显的相关性,而常规基台的应力分布随着种植深度的下移呈逐渐上移的趋势;各个种植深度中两组种植体、松质骨的应力分布情况基本相似,与种植深度无明显的相关性;在平台转换组中,皮质骨的应力分布随种植深度的下移而下移,而常规组中应力始终集中于牙槽嵴顶与基台相接处没有变化,且其应力分布比平台转换组集中。水平加载下各模型的应力分布规律与垂直组相似,不同的是基台、种植体的最大应力值主要集中在他们相应部位的唇侧。皮质骨中,唇侧的应力明显较垂直加载组集中。结论平台转换种植体植于牙槽嵴顶下水平可以改善牙槽嵴顶应力分布情况,比常规种植体有明显的优势,水平方向的分力将增加牙槽嵴顶骨组织受力,应尽量避免。

Objective In this experiment,the model of Platform Switching Implant was simulated by adopting three-dimensional（3D） finite element method and the stress distribution of implants planted in different depth was analyzed when the platform switching implant system was applied with different loading in front maxilla.Method By using the Solidworks 2007 and Ansys Workbench11.0 software to simulate the 3D finite element models,the stress distribution of implants in the form of platform switching as experimental group and traditional abutment as control group which were respectively planted into the level of alveolar ridge（bone level）,1 mm below bone level（minus 1） and 2 mm below bone level（minus 2） were analyzed.Results For platform switching implants,the stress of cortical bone was effectively reduced and smaller as the imlpant was planted deeper,while the traditional abutment did not change significantly with deeper planting level.Under vertical loading,the stress distribution in each model’s abutment of platform switching was basically similar,having no significant correlation with theplanting depth,while the stress distribution in the traditional abutment had a significant change： gradually trending up with deeper planting level;the stress distribution of two groups of implants in each planting level and cancel-lous bone was basically similar,having no significant correlation with the planting depth;the stress distribution of cortical bone was shifted down with deeper planting level for platform switching group,while in the traditional abut-ment group,the stress distribution of cortical bone always focused on the joint between alveolar ridge top and a-butment,which was more concentrated than that in platform switching group.The stress distribution under hori-zontal loading was similar to that under vertical loading,and the only difference was in that the maximum stress distribution of abutment and implant was mainly concentrated in their corresponding labial parts.In cortical bone,the buccal stress was obviously more concentrated than that in the vertical loading group.Conclusions Platform switching implant planted below the alveolar ridge top can improve the stress distribution,which has obvious ad-vantages over the traditional abutment form.But the component force in horizontal direction would increase the stress on the labial part of alveolar ridge,and should be avoided.