基于计算机三维重建技术的固定桥有限元实体建模

目的：研究螺旋CT扫描图像的固定桥计算机三维重建的方法。方法：采用美国PQ6000型螺旋CT扫描机，自下颌颏部下缘开始至鼻骨底做连续横断超薄扫描，得到人牙齿的二维CT图像。应用图像处理与识别合成软件，读取二维CT图像数据文件，通过灰度分割方法对二维图像进行边缘提取，再利用三维表面重建算法对所截取的二维CT图像进行三维重建，最终获得固定桥的三维重建影像。结果：获得了包括牙齿、牙周膜、牙槽骨在内的下颌后牙三单位固定桥的三维有限元数学模型。模型可以根据要求任意进行旋转、缩放、透视、剖开等多种方式观察，并可以按照不同研究目的和要求对模型进行修改和调整。结论：基于螺旋CT扫描图像的固定桥计算机三维重建，可为有限元实体建模提供快捷、方便的方法。

Three-dimensional rebuilding of fixed bridge based on the digital images by spiral CT

Objective:To study the three dimensional rebuilding method of fixed bridge based on the digital images by spiral CT. Method:By the PQ6000 spiral CT,successive cross-sectional scanning was made from the inferior edge of the mandibular chin to the bottom of the nasal bone to obtain the two-dimensional digital images. Using the image processing and recognition software,two-dimensional CT image data file was established. Two-dimensional gray image segmentation method was adopted for edge detection. Further,three-dimensional surface reconstruction algorithm was used for the three-dimensional reconstruction of the fixed bridge by intercepted two-dimensional image. Result:Three-dimensional image of fixed bridge,including abutment teeth,periodontal membrane and alveolar bone,was obtained,which was rather vivid in every detail,and could be rotated,dissected,perspected,and intercepted optionally. It made the observation of images from different angles as possible. The reconstruction showed satisfactory replicating effects. Conclusion:Three-dimensional reconstruction of the fixed bridge by digital scanning of spiral CT could provide us a convenient and fast method for finite element model establishment.