不同种植位点下附着体类型对短种植体覆盖义齿的应力影响

Effect of Attachment Type on the Stress of Short Implant-assisted Removable Partial Dentures at Different Implant Positions

目的:研究不同种植位点下附着体类型对于短种植体辅助固位式覆盖义齿修复KennedyⅠ类缺失时的应力分布效果。方法:建立短种植体辅助固位式覆盖义齿修复下颌双侧前磨牙及磨牙全部缺失的三维有限元模型,根据种植位点(位点A:第二前磨牙区、位点B:第一磨牙区、位点C:第二磨牙区)及附着体类型构建9个实验组:A-Brevis、A-Locator、A-Magfit、B-Brevis、B-Locator、B-Magfit、C-Brevis、C-Locator、C-Magfit,同时建立传统可摘局部义齿模型(RPD组)作为对照。分析各部件的应力分布情况,读取最大von Mises应力数值及位移数值。结果:建立了短种植体、附着体、可摘局部义齿、牙体组织、牙周组织、黏膜、皮质骨、松质骨的三维有限元模型。垂直及斜向载荷下,均有RPD组义齿位移量大于各实验组;斜向载荷下,Magfit组义齿位移量大于Brevis组及Locator组,而短种植体-骨界面应力较小,黏膜应力及短种植体周围皮质骨应力较大;短种植体位于位点C时短种植体-骨界面应力及短种植体应力较小,黏膜应力较大。结论:短种植体辅助固位式覆盖义齿可明显提高义齿的固位与稳定性,Magfit附着体更利于侧向力的传递,有助于提高短种植体辅助固位式覆盖义齿的长期成功率;理想条件下位点C更适合咬合力的分散。

Objective:To compare influences of attachment type and different implant sites on the stress distribution among all supporting structures.Methods:A three-dimensional finite element model of a short-implants-assisted removable partial denture was established to restore Kennedy classⅠdentition defect,and nine experimental group models were constructed according to the implant positions(position A:the second premolar area,position B:the first molar area,position C:the second molar area)and attachment types(Brevis,Locator,and Magfit).A removable partial denture model was established as the control.The stress distribution of each component was analyzed,and the maximum von Mises stress values and displacement values were recorded.Results:Three-dimensional finite element models of short implant-assisted removable partial denture were established.Under vertical and oblique loads,the denture displacement was greater in the RPD group than in the experimental groups;under oblique loads,the denture displacement was greater in the Magfit groups than in the Brevis and Locator groups,while the implant-bone interface stress was smaller and the mucosa stress and cortical bone stress around the short implant were greater;the implant-bone interface stress and short implant stress were smaller,and the short implant stress was greater when the short implant was located at position C.Conclusion:Short implants-assisted removable partial dentures can significantly improve the retention and stability of the denture,and magnetic attachments are more beneficial to the long-term success of short implants.Position C is better suited for dispersion of occlusal forces.