摘要目的 探讨在上颌前牵引联合横向扩弓作用力下,骨缝结构对单侧唇腭裂(unilateral cleft lip and palate,UCLP)患者颅上颌复合体位移变化和应力分布的影响.方法 选择1例左侧唇腭裂患者进行颅面部CT扫描,利用所得CT扫描数据分别建立一个包含或不包含骨缝结构的颅上颌复合体的三维有限元模型,在腭中缝扩开6 mm情况下,于双侧第一双前磨牙处分别施加一个500 g、与咬合平面呈20°向前下的上颌前牵引力,利用Ansys12.0分析颅面复合体的位移变化和应力分布.结果 建立了含或不含骨缝唇腭裂颅上颌有限元模型;在上颌前牵引联合横向扩弓作用力下,有骨缝和无骨缝模型上颌均发生了明显向前、下的位移,在水平、矢状、垂直三个方向上的位移均有从下至上递减趋势;且唇腭裂侧位移比无唇腭裂侧位移大;有骨缝模型明显比无骨缝模型位移量大.在二力联合作用下,有骨缝模型的骨缝区均同时存在压应力和拉应力,唇腭裂侧骨缝和无唇腭裂侧骨缝的应力分布趋势基本一致,但唇腭裂侧骨缝应力较无唇腭裂侧骨缝应力大.结论 本实验从生物力学角度证实了骨缝在颅上颌复合体生长改良中具有重要意义.

abstractsObjective To investigate the biomechanical influence of circum-maxillary sutures on the reaction of maxillary protraction and maxillary expansion.Methods One male patient aged 9 with left complete lip and palate cleft was selected.CT scan on the head was taken at 0.75mm intervals.Two FEM models of the cranio-maxillary complex with or without sutures were constructed from CT data with the following softwares:Mimics 10.0,Geomagic studio 12.0,Solidworks (version 2011) and E-feature Biomedical Modeler.Both models were loaded by a maxillary protraction force (500 g per side,20 degrees downward and forward from the occlusal plane) after the mid-palatal suture was expanded 6mm by maxillary expansion.Displacement of cranio-maxillary complex and stress distribution of the circum-maxillary sutures were investigated.Results (1) Three-dimensional finite element models of UCLP cranio-maxillary complex with or without sutures were established based on CT data.(2) The displacement of cranio-maxillary structures in the model with sutures was more obvious than that without sutures; (3) In both models,the UCLP cranio-maxillary complex moved forwards and downwards obviously,whose amount decreased gradually from bottom to top.The distance of displacement on the cleft side was larger than that on the non-cleft side; (4) Both tensile and compressive stresses were found in both models around the sutures.Though the distribution of the stress were similar in cleft and non-cleft side,the magnitude of the former was larger than the latter.Conclusions The research hints that circum-maxillary sutures play an important role in the process of growth modification in the prospective of biomechanics.