基于有限元分析的牙种植体基台锥度过盈配合的力学机理研究

Mechanics of The Tapered Interference Fit in Dental Implants Analysed by Finite Element Method

本文依据基台-植入体连接面锥度和接触面尺寸变化,研究植入体接触面的应力变化规律和力学机理。以Astra品牌牙种植体为范型,通过力学等效原理做合理的简化,并使用Ansys Workbench 19.2版软件,应用二维平面的轴对称模型作分析,采用五种锥度和四种基台-植入体接触面尺寸为设计变数,观察当一般咬合力200 N和最大咬合力580 N下接触面的范氏等效应力值。分析结果表明施以上述二种咬合力状况下,锥度越小,接触面应力值越大;接触面尺寸愈大,接触面应力值越小。在咬合力200 N状况下,各种锥度和接触面尺寸的结构的接触面应力值皆未超出屈服应力。而在咬合力580 N状况下,根据各种锥度的应力值变化情形,建议适用锥度范围为9°至12°;锥度小于9°、接触面尺寸在3.5 mm以下的结构会有应力过大产生连接面破坏的风险。综合上述,本文提供基台-植入物连接面过盈配合的五种锥度变化及四种接触面尺寸的接触面应力分析结果,未来可以做为牙种植体的设计参考,避免高应力值造成种植体破坏的风险。

This study tried to figure out the influence of angles of taper and the contact stress of abutmentimplant’s connect surface.Astra implant system being employed as models were simplified by the mechanical equivalence principle and analysed by software Ansys Workbench 19.2 edition in an axial symmetrical 2D plane model.The contact stresses were investigated with moderate and the extreme two occlusal loads 200 N and 580 N by means of 5 various taper angles of abutments and 4 kinds of abutment abutment-implant’s connect surface lengths.The results implied smaller taper angles caused higher contact stresses,and longer contact surface length caused lower contact stresses under two kinds of occlusal loads.All taper angles and all contact surface lengths of abutment-fixture structures,contact stresses were not achieved yield stress under 200 N occlusal load.Suitable taper angle ranged from 9°to 12°suggested for use under 580 N occlusal load.Taper angle smaller than 9°and contact surface length shorter than 3.5 mm might cause abutment-fixture structures yield.As the results this study indicated could be dental implant design criteria to avoid a structure damage in an abutment-fixture connection part with high contact stresses.