上颌无牙颌All-on-Four远中种植体不同倾斜角度和长度的三维有限元应力分析

Three-dimensional finite element stress analysis of All-on-Four distal implants with different tilt angles and lengths on edentulous maxilla

目的:应用三维有限元法研究上颌无牙颌All-on-Four远中种植体在不同角度和不同长度模型中的应力分布。方法 :选择1例上颌无牙颌女性患者,采集数据,三维重建,构建上颌无牙颌"All-on-Four"种植修复的三维有限元模型。按照远中种植体角度和长度不同分为4组:A组30°11.5 mm,B组30°13.0 mm,C组45°11.5 mm,D组45°13.0 mm。100 N垂直静载荷分别加载于第一、二前磨牙及第一磨牙上模拟咀嚼受力,应用ABAQUS软件测算种植体在上颌无牙颌模型上的等效应力值。结果:垂直载荷下,应力集中在种植体颈部周围骨皮质区;远中种植体长度增加,各区域应力缓慢下降;远中种植体倾斜角度增加,应力分布分散,种植体颈部和根尖区应力明显减小。结论:远中种植体长度增加对应力分布和大小的改变并不显著,远中种植体倾斜45°比倾斜30°更有利于应力分散。

Objective：To study stress distribution of All-on-Four distal implants with different tilt angles and lengths on edentulous maxilla using the three-dimensional finite element method. Methods：A female patient with edentulous maxilla was selected. After data collecting and three-dimensional reconstruction,a three-dimensional finite element model of edentulous maxilla with All-on-Four implant restoration was established. According to the tilt angles and lengths of the distal implants,there were four groups：Group A：30°,11.5 mm; Group B：30°,13 mm; Group C：45°,11.5 mm; Group：D 45°,13 mm. 100 N vertical static force was loaded on the first premolar,the second premolar and the first molar to simulate chewing, respectively Equivalent stress values of implants on the edentulous maxilla model were calculated using ABAQUS software. Results：Under the vertical static load,stress concentration was found around the implant neck in the cortical bone area. With the increase of the distal implant length,the stress decreased slowly in all regions. With the tilt angle of distal implant increasing,the distribution of stress became more dispersed and the stress in implant neck and apical areas significantly reduced. Conclusion：The stress distribution and magnitude of distal implant did not change significantly with the increase of the implant length,while the implant tilt angle of 45° was more favorable for stress dispersion than the implant tilt angle of 30°.