不同载荷条件对后牙单种植体义齿下颌骨应力的影响

Influence of various loading conditions from posterior single tooth implant on stress distribution in the mandibula

目的探讨垂直和斜向载荷作用于下颌后牙单种植体支持式义齿不同载荷点对下颌骨应力分布的影响。方法应用部分下颌骨CT扫描图像建立下颌骨的三维有限元模型,根据测量数据建立种植体的三维有限元模型,建立半解剖式种植义齿牙冠的三维有限元模型;在下颌第一恒磨牙种植体义齿各咬合点分别加垂直和斜向载荷,计算下颌骨所受的最大等效应力。结果在垂直和斜向载荷作用下,下颌骨的最大等效应力位于颈周骨皮质的上方;在相同的垂直斜向载荷下,不同咬合点加载时,下颌骨上所产生的最大等效应力有明显差异;同一载荷点在大小相同、方向不同的载荷作用下,下颌骨的最大等效应力有明显差异。结论在垂直和斜向载荷作用下,下颌骨的最大等效应力位于颈周骨皮质的上方,向根尖部递减;远中尖斜向加载时颈周骨皮质的上方的等效应力最大;载荷方式是影响颈周骨皮质应力分布的重要因素。

Objective To investigate the stress distribution in the mandibula with oblique and vertical forces imposed respectively in different positions of the occlusion surface of the posterior single tooth replacement. Method The three-dimensional（3-D） finite element method （FEM） was used to reconstruct the 3-D models of the mandibula, the first inferior molar and the implant. The max EQV of the mandibula were calculated when oblique and vertical forces were applied to different positions of the occlusion surface of the implant. Result The max EQV of the mandibula were found at the neck of the mandibula around the implant under both oblique andvertical load; The max EQV were significantly different at different points with the same vertical load or with the same load at the different directions. Conclusion The max EQV of the mandibula are at the neck of the mandibula around the implant and decrease progressively from the neck to the bottom under the oblique and vertical load; The largest max EQV was found at the neck of the mandibula around the implant when the same load was applied to the distal locations; the various loading conditions play the important role that can influence the stress distribution at the neck of the mandibula around the implant.