6颗种植体支持的上颌无牙颌固定义齿应力分布研究

目的:分析种植体位置变化时,6颗种植体支持的上颌无牙颌固定义齿的应力分布.方法:选择一名牙列缺失、牙槽骨中度吸收的志愿者,对其头颅部进行CBCT扫描,并利用一系列计算机软件进行数据转换,完成上颌骨三维实体模型的重建.设计8种不同位置种植体支持的固定义齿,建立8个三维有限元模型,分析种植体、上颌骨和固定义齿的应力分布情况.结果:远中没有悬臂的模型比有悬臂的模型的应力差值小;8种位点设计的模型都是应力集中在磨牙区种植体,种植体的应力集中点都是种植体颈部,且是偏向于颊侧.种植体的应力都是磨牙＞前磨牙＞前牙;在8种位点设计的模型中,种植固定义齿和颌骨位移都是集中在前牙区,种植固定义齿的位移是从前牙区向后牙区逐渐变小;8种模型的种植体应力都表现为以压应力为主.模型Ⅰ种植体(位点13、15、17、23、25、27)分散型排列,避免了远中悬臂的设计,6颗种植体的应力分布最均匀.结论:种植体植入位点于13、15、17、23、25、27,是8种方案中最佳的植入位点方案.

The stress distribution in the fixed denture of edentulous maxilla supported by six implants

Objective:To analyze the stress distribution in the fixed denture of edentulous maxilla supported by 6 implants at different implant position.Methods:The skull of a volunteer with total anodontia and moderate alveolar bone absorption was scanned by CBCT.Computer software,Abaqus 6.9,Geomagic Studio 12,and Mimics10.01,were applied for data processing and reconstruction of a 3D finite element model of implant-supported fixed denture with 6 implants in different location;and then,the stress distribution was analisized.Results:3D finite element model of edentulous maxillary implant-supported fixed bridge with good geometric similarity was established.The implant neck bone interface stress value of the distal of the implant fixed bridge at the molar area,the stress concentration area,was the maximum.The main stresses were compressive in the cortical bone adjacent to the mesial or the distal implants.The shift of the denture decreased from anterior to posterior.In model Ⅰ (implants at 13,15,17,23,25 and 27) distal cantilever was not used and the stress distribution was the evenest.Conclusion:The implant position at 13,15,17,23,25 and 27 of edentulous maxillary 6-implants-supported fixed bridge was the best for the stress distribution among the 8 models.