植入位点及轴向对不同牙槽窝形态上中切牙即刻种植即刻负重应力影响的三维有限元分析

目的 基于三维有限元法，分析并探讨不同牙槽窝形态下，上颌中切行牙即刻种植即刻负重时，植入位点及轴向对种植体、基台、中央螺丝、牙冠应力分布的影响。方法 参照1名健康成年人的口腔CBCT影像资料；建立偏唇型、中间型、偏腭型三种牙槽窝形态的上颌中切牙即刻种植即刻负重的三维有限元模型；模拟不同植入位点(根尖位点、偏腭/唇侧位点)及轴向(牙长轴、牙槽骨长轴);对已建立的模型以100 N的力进行应力加载；应用ANSYS软件分析种植体、基台、中央螺丝、牙冠的应力值。结果 成功建立12个不同牙槽窝形态的上颌中切牙即刻种植即刻负重三维有限元模型；牙槽窝偏唇型及偏腭型的上颌中切牙行即刻种植即刻负重时，沿牙槽骨长轴偏腭/唇位点进行植入，种植体及其上部结构所受应力最小；中央型上颌中切牙行即刻种植即刻负重时，沿牙长轴偏腭位点进行植入，种植体及其上部结构所受应力最小。结论 不同牙槽窝形态、植入位点及轴向，都会对上颌中切牙即刻种植即刻负重种植体及其上部结构生物力学特点产生影响。医生应针对不同牙槽窝形态制定不同植入轴向及植入位点的手术方案。

Three-dimensional finite element analysis of the influence of implant site and axial direction on the immediate weight bearing stress of central incisors in different alveolar fossa shapes

Objective To analyze and investigate the effects of implant location and axial direction on the stress distribution of implants, abutments, central screws, and crowns during immediate loading of maxillary mesial incisors with different alveolar fossa morphology based on three-dimensional finite element method. Methods Referring to the oral CBCT images of a healthy adult, a three-dimensional finite element model was established for immediate implant loading of maxillary central incisors with three alveolar fossa morphs: labial, intermediate, and palatal; different implant sites(apical site, palatal/labial site) and axes(tooth long axis, alveolar bone long axis) were simulated; the established model was loaded with a force of 100 N. ANSYS software was applied to analyze the stress values of the implants, abutments, central screwss, and crownss. Results The 3D finite element models of 12 maxillary central incisors with different alveolar sockets were successfully established;the implants and their superstructures were least stressed when the maxillary central incisors with partial labial and partial palatal shape were placed along the long axis of the alveolar bone in the palatal/labial position for immediate implant loading;the implants and their superstructures were least stressed when the maxillary central incisors with central shape were placed along the long axis of the tooth in the palatal position for immediate implant loading. The implant and its superstructure were subjected to the least stress when the implant was placed along the long axis of the tooth in the immediate loading position. Conclusion The bio-mechanical characteristics of the implant and its superstructure are influenced by the different socket morphology, implantation sites and axes. Therefore, in clinical practice, different implantation axes and implantation sites should be developed for different socket morphs.