根尖切除手术导板的计算机辅助设计及三维打印

Computer aided design and three-dimensional printing forapicoectomy guide template

目的:基于多源数据融合、计算机辅助设计(computer aided design,CAD)和熔融沉积工艺制造(fused deposition modeling,FDM)技术,建立一种根尖切除手术导板的设计制作方法,通过离体模型实验初步评价导板的可行性。方法:将一颗已完善根管治疗的离体上前牙经光学扫描后,灌入根尖切除手术石膏模型,进行该石膏模型的锥形束CT(cone-beam computed tomography,CBCT)扫描和光学扫描,将各种数据导入Geomagic Studio 2012软件中,利用多源数据融合技术虚拟还原离体牙、牙列、牙槽骨和牙龈的三维位置关系,完成根尖切除手术导板三维设计。运用FDM技术,三维打印聚乳酸(polylactic acid,PLA)材质的根尖切除手术导板。在手术导板引导下于石膏模型上行根尖切除,术后抠除离体上前牙,进行光学扫描。通过测量距离、测量夹角功能来计算根尖切除长度和角度,并与预设切除长度和角度进行对比。结果:沿预设的牙长轴方向,根尖切除长度为2.88 mm,与预设切除的3 mm相差0.12 mm,根尖切除平面与牙长轴夹角为77.9°,与预设切除的90°相差12.1°。结论:结合多源数据融合、CAD及FDM技术,成功建立了一种根尖切除手术导板的数字化设计和制作方法,设计路线和制作方法可行,为国产根尖切除手术导板数字化设计专用软件的开发提供了技术和方法的参考。

Objective： To establish an apicoectomy guide template design and manufacturing method,based on multi-source data fusion, computer aided design （CAD） and fused deposition modeling （FDM）. The feasibility of the guide template was preliminary evaluated by the in vitro model experiment. Methods： An extracted upper anterior tooth,after root canal treatment,was optical scanned,after which the extracted upper anterior tooth was poured in an apicoectomy plaster model. Cone-beam computed tomography （CBCT） scanning of the apicoectomy plaster model was performed,after which optical scanning of the plaster model for apical resection surgery was carried out. All of the relevant CBCT and optical scanning data of the extracted upper anterior tooth and the apicoectomy plaster model were introduced into the Geomagic Studio 2012 software. The multi-source data fusion technology was used to virtually simulate the three-dimensional positional relationship of the extracted tooth,the dentition,the alveolar bone and the gingival,based on which,the three-dimensional design of the apicoectomy guide template was completed in the Geomagic Studio 2012 software. With the technology of fused deposition modeling,the apical resection surgical guide template was three-dimensionally printed with the material of polylactic acid （PLA）. Under the guidance of the surgical guide template,the root apical resection was performed on the plaster model. After the apicoectomy,the extracted upper anterior tooth was taken off from the apicoectomy plaster model and then was given the optical scanning. The apical resection length and angle were calculated by the function of distance measurement and angle measurement,and the results were compared with the preset values. Results： The length of the apical resection was 2. 88 mm along the direction of the long axis of the tooth,which was 0. 12 mm lower than the preset 3 mm. The included angle between the apical resection plane and the long axis of the tooth was 77. 9°,12. 1° lower than the preset 90°. Conclusion： This study successfully established a digital design and production method of apicoectomy guide template by combing the multi-source data fusion,CAD and FDM technology. The design route and the production method are feasible. The study will provide a technology and methodology reference for the development of domestic special software for the digital design of apicoectomy guide template.