2种前方牵引装置前牵引唇腭裂患者上颌骨的三维有限元分析

目的:建立含微钛板支抗和牙支持式前牵引装置的唇腭裂颅上颌复合体三维有限元模型,探讨其前牵引生物力学效应.方法:选取1例恒牙早期唇腭裂男性志愿者,进行锥形束CT(cone beam CT,CBCT)扫描,构建模型,模拟加力,分析位移变化及应力分布.结果:建立了含微钛板支抗和牙支持式前牵引装置的单、双侧唇腭裂颅上颌复合体三维有限元模型.前牵引时,上牙弓内缩;微钛板支抗模型上颌中上部位移量大于牙支持式模型,后者上颌前部及上尖牙位移量大于前者.微钛板支抗模型应力集中于上颌骨中上部,牙支持式模型的应力集中在上颌尖牙点,且前者应力值及分布范围均大于后者.双侧唇腭裂模型上前牙牙槽嵴处位移小于单侧唇腭裂模型,后者患侧位移和应力分布范围均大于健侧.结论:本研究构建的模型生物力学仿真性好,为唇腭裂上颌骨前牵引治疗的生物力学研究提供了良好的实验载体.微钛板支抗上颌骨前牵引以骨性作用为主,牙支持式上颌骨前牵引以牙性作用为主,前者更有利于效果稳定和侧貌改善.

Biomechanical effect of 2 anchorages on maxillary protraction with cleft lip and palate: a finite element analysis

PURPOSE:To establish cranio-maxillary complex finite element models (FEMs) in cleft lip and palate (CLP) patients with miniplate and tooth-borne anchorage (MA&TA),and to investigate the biomechanical effects on maxillary protraction.METHODS:The protracting process was simulated on FEMs established from a male patient's cone beam CT (CBCT) data to analyze the displacement and stress from different appliances.RESULTS:Four FEMs of unilateral cleft lip and palate (UCLP) or bilateral cleft lip and palate (BCLP) patients' cranio-maxillary complex with MA and TA were established.The maxillary arch on both sides of the cleft moved towards the cleft side during protraction,which was more obvious in the miniplate anchorage three-dimensional finite element models (FEM-MA) than the tooth-borne anchorage three-dimensional finite element models (FEM-TA).The amount of forward,downward displacement of the inferior orbital rim,paranasal area and middle maxilla point in the FEM-MA was larger than that in the FEM-TA,while the amount of forward displacement of premaxilla and upper canine in the FEM-TA was larger than that in the FEM-MA.The FEM-MA exhibited an orthopedic effect with more favorable stress distribution on the middle maxilla point while the FEM-TA showed a dentoalveolar effect with prominent stress distribution on the upper canine point.In addition,the FEM-MA showed a larger stress distribution area and sutural stress value than did the FEM-TA.The UCLP models showed an asymmetric pattem in stress distribution and displacement,which was larger on the cleft side than that on the non-cleft side.The amount of displacement of premaxilla in the BCLP models was smaller than that in the UCLP models.CONCLUSIONS:The established models have high geomagic and biomechanical similarities.It would be more advantageous to obtain more aesthetic outcomes and better stability using the miniplate anchorage.