基于影像学牙周膜解剖特征快速提取活体牙三维牙根形态的方法

发布时间：2018-12-13 09:24

【摘要】：目的:探索一种基于牙周膜生理影像特征快速提取活体牙根三维形态的新方法,并对该方法的提取精度进行评价。方法:收集口腔正畸临床减数拔除的完整离体牙齿15颗,其中单根牙11颗、双根牙4颗,使用牙颌模型扫描仪获得高精度(0.02 mm)牙根三维数字模型。在牙齿拔除前为患者拍摄大视野锥束CT(0.3 mm体素分辨率),应用Mimics 18.0医学影像学软件,基于减数牙齿的根骨和牙周膜阈值蒙版,运用形态学运算、布尔运算及智能扩展运算等功能获得牙根三维数字模型。在Geomagic Studio 2012软件中,对应用本研究方法提取的活体牙根三维模型与同名离体牙根三维扫描模型进行三维形貌偏差的比较和三维尺寸误差的测量,评价该提取方法的精度。结果:提取的15颗牙根三维形貌偏差平均为0.22 mm,近远中径误差为0.46 mm,颊舌径误差为0.36 mm,根长误差为-0.68 mm,单牙提取时间约为2~3 min,基本可以满足口腔临床对牙根重建的精度要求。结论:建立了基于活体牙影像数据快速提取牙根三维形态的新方法,一定程度上简化了传统手工提取的步骤,提高了单牙牙根提取的效率和自动化程度,其针对全牙列提取的方法策略有待进一步研究。
[Abstract]:Objective: to explore a new method for rapid extraction of three dimensional morphology of living teeth based on the physiological image of periodontal ligament, and evaluate the accuracy of the method. Methods: a total of 15 totally extracted teeth were collected, including 11 single teeth and 4 double teeth. A high precision (0. 02 mm) digital model of tooth root was obtained by maxillary model scanner. Large field cone-beam CT (0.3 mm voxel resolution) was photographed for patients before tooth extraction. Mimics 18.0 medical imaging software was used. The threshold value of root bone and periodontal membrane of subtraction teeth was masked, and morphological operation was used. Boolean operation and intelligent extended operation are used to obtain the root 3D digital model. In the software of Geomagic Studio 2012, the 3D model of the living root and the model of the same name were compared with the model of the same name in the software Geomagic Studio 2012, and the accuracy of the method was evaluated. Results: the average deviation of 3D morphology of 15 extracted teeth was 0.22 mm, the error of proximal and distal diameter was 0.46 mm, the error of root length was 0.36 mm, the error of root length was -0.68 mm, the extraction time of single tooth was about 2m3 min,. It can meet the precision requirement of dental root reconstruction. Conclusion: a new method based on living tooth image data was established to quickly extract the three-dimensional shape of tooth root. To some extent, the traditional manual extraction process was simplified, and the efficiency and automation of single tooth root extraction were improved. The method and strategy of total dentition extraction need further study.
【作者单位】：北京大学口腔医学院·口腔医院口腔医学数字化研究中心口腔修复教研室正畸科口腔数字化医疗技术和材料国家工程实验室卫生部口腔医学计算机应用工程技术研究中心口腔数字医学北京市重点实验室;
【基金】：国家自然科学基金(81300921)资助~~
【分类号】：R781

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