下颌角骨折坚强内固定后应力遮挡效应的三维有限元分析

摘要

目的:分析下颌角骨折坚强内固定时的应力分布,探讨可能发生的应力遮挡效应,为临床应用提供参考.方法:运用三维有限元软件对下颌角骨折采用双小型钛接骨板与小型板+重建板2种内固定方法,分析在骨折愈合的早、中、后3个时期的应力分布,计算各种情况下的应力遮挡率.结果:下颌角骨折采用双小型板固定时,骨折愈合早、中、后3个时期的应力遮挡率分别为88.46%、9.24%、8.99%;采用小型板+重建板固定时,3个时期的应力遮挡率分别为89.67%、11.81%、11.11%.结论:下颌角骨折坚强内固定后应力遮挡效应是始终存在的,随着骨折的愈合,下颌角骨折各种内固定系统的应力遮挡率逐渐减小.且同一骨折愈合时期,小型板+重建板的应力遮挡率大于双小型板,即接骨板的强度越高,应力遮挡作用越明显.%Objective: To analysis the stress distribution and the stress-shielding of rigid intemal fixation for fractures of mandibular angle.Methods: The stress distribution of rigid internal fixation with double titanium miniplates and single titanium miniplate plus single reconstruction plate, at the initial, middle and later stages of fracture healing in madibular angle was analysed and the rate of stressshielding under all these conditions was calculated by three-dimensional finite element model and software.Results:When fixed with double titanium miniplates, the rates of stress-shielding of fractures of mandibular angle at the initial, middle and later stages of fracture healing was 88.46％ , 9.24％ and 8.99％ respectively.When fixed with single titanium miniplate plus single reconstruction plate, that was 89.67％, 11.81％ and 11.11％ respectively.Conclusion:The effect of stress-shielding after rigid internal fixation for fracture of mandibular angle always exists.With the fracture healing, the rate of stress-shielding gradually decreases, at the same period of fracture healing, the rate of stress-shielding of single titanium miniplate plus single reconstruction plate is higher than that of double titanium miniplates.The stronger the fixation for fiactures is, the more obvious the effect of stress-shielding is.