半侧上颌骨缺损赝复体修复固位方案的生物力学评价

目的 对3种单侧上颌骨缺损赝复体修复方式——卡环固位、一根/两根颧种植与卡环联合固位进行生物力学评价。方法 基于CT扫描数据建立正常人颅骨的三维有限元模型，通过三维有限元法计算分析3种重建模型中上颌复合体的应力分布，综合比较赝复体、基牙、卡环、种植体、颧骨的应力水平。结果 单一的卡环固位，基牙应力峰值达130.7 MPa，赝复体产生位移4.439 mm，卡环应力峰值达452.4 MPa，健侧眶缘应力为23.32 MPa；加入一根颧种植后，卡环应力减小至118.1 MPa，基牙应力峰值为31.12 MPa，健侧眶缘应力仅为5.387 MPa。两根颧种植体固位方式下，颧骨应力由66.11 MPa减小到48.12 MPa；颧种植体上的最大应力也由500.2 MPa降至313.8 MPa。 结论 颧种植与卡环联合固位，颌面骨骼应力分布更符合咬合力传导规律。研究结果将为人体上颌单侧缺损重建方案设计和优化提供重要参考数据。

Biomechanical evaluation on prosthetic retention program for hemi-maxillary defects

Objective To make biomechanical evaluation on three prosthesis retention schemes for unilateral maxillary defects-clasp retention, one or two zygomatic implants and zygomatic implant and clasp united retention. Methods A three-dimensional (3D) finite element model of normal human skull was constructed based on CT scan data. The maxillary complex stress distributions on three reconstructed models were calculated and analyzed by 3D finite element method to make comprehensive comparison on stress level of the prosthesis, abutment, clasp, implants and zygoma. Results For single clasp retention, peak stress of the abutment was 130.7 MPa, and displacement of the prosthesis was 4.439 mm, while peak stress of the clap was 452.4 MPa, and stress of the contralateral orbital rim was 23.32 MPa. After one zygoma was implanted, the stress of the clap was reduced to 118.1 MPa, while peak stress of the abutment was 31.12 MPa, and stress of the contralateral orbital rim was only 5.387 MPa. For two zygomatic implant retention, zygomatic stress was decreased from 66.11 MPa to 48.12 MPa, and the maximum stress on the zygomatic implants was reduced from 500.2 MPa to 313.8 MPa. Conclusions For zygomatic implant and clasp united retention, the maxillofacial skeleton stress distributions were more consistent with the rules of bite force transduction. The research findings will provide important references for design and optimization of human unilateral maxillary defect reconstruction program.