根据CT扫描数据及印模三维重建牙列数字模型精度的初步研究

The preliminary study of dentition surface reconstruction from CT scans and cast scanning image

目的:评价根据CT扫描数据和牙列印模重建牙列数字模型的精度。方法:以OKIO-V-100三维光学扫描系统扫描猴牙列标本获取标准模型;根据螺旋CT、锥束CT扫描数据重建颌骨及牙列三维数字模型;制取猴牙列标本印模,灌制石膏模型,通过OKIO-V-100三维光学扫描系统扫描重建牙列形态。分别将CT扫描重建的数字图像、石膏模型扫描重建图像与标准模型的牙列图像拟合。拟合图像中使用不同颜色标记不同大小的误差值,并生成误差直方图。在拟合图像中以模拟平面截取牙列形态,分析不同位置的平面所截取的牙列数字模型与标准模型的体积之差及RVD/VS。结果:根据螺旋CT、锥束CT扫描数据重建牙列三维数字模型的RVD/VS可达40%以上,随着模拟平面龈向移动,RVD/VS有变小的趋势;再根据石膏模型扫描重建的模型中,随着模拟平面龈向移动,RVD/VS有变大的趋势。结论:根据螺旋CT、锥束CT扫描图像重建的牙列数字模型,与标准模型相比都有较大程度的放大;不同位置的平面所截取牙列图像的变形程度是不一致的,CT扫描与印模相结合重建三维牙颌模型可能是获得较高精度三维牙颌数字模型的方法。

Objective： The aim of this study was to evaluate the dimensional accuracy of dentition image reconstruction from CT scans and cast scanning image.Methods： A simian dental arch was prepared and digitized as the standard model using OKIO-V-100 3D optical scanner.Impression was made for stone cast using silicone impression material,and the cast was digitized using the optical scanner.Dentition images were also reconstructed from spiral CT and cone-beam CT scans.The dentition images from impression and CT were superimposed onto the standard image.Distribution patterns of dimensional discrepancy were presented using histogram and different colors.The superimposed images were cut using different cross-section.The RVD/VS was analyzed.Results： In the images reconstructed from CT scans,the RVD/VS were more than 40%,compared with the standard image.If the cross-section moved toward gingival direction,RVD/VS declined,while in the image from the cast,RVD/VS increased.Conclusion： Compared with the standard model,the digital dentition images reconstructed from both spiral CT and cone-beam CT are enlarged,and the enlargement is inhomogeneous among different cross-sections.The combination of images from cast scans data and CT scans may be a choice to obtain high quality images of tooth and bone.