open access

https://hdl.handle.net/2115/52156

Construction method of a tooth crown model using data generated by micro-focus CT ― Voxel models of anterior and premolar teeth ―

英語

Shape Measurement

2012-09

Hokkaido association for dental science

Hokkaido journal of dental science

33(1)

17-23

Currently, a number of dental CAD/CAM systems are in operation in Japan. Many of them adopt a non-contact optical system using a CCD camera and light patterns to measure the model teeth. One disadvantage of this method is that it is difficult to measure the parts in the shade. However, this problem can be solved if we can carry out measurements using 3D CT. In this study we have examined how to construct a 3D model of a tooth crown shape using micro-CT data. An R_mCT2 micro-CT manufactured by Rigaku Corporation was used under maging conditions of FOV10（φ10 mm×H10 mm）, 90 kV tube voltage and 160 μA tube current. Basic study models manufactured by KaVo Dental GmbH were used in the imaging, which was carried out in two phases, as the size of the artificial teeth was greater than that of the FOV. The image data was output in 512 slices in the form of DICOM files, and transferred to a personal computer. We examined the CT values of all the voxels of all images using software we developed ourselves. Based on the results, we determined the threshold by comparing the distribution of the CT values of the artificial teeth area with those of the remaining area in each image, and extracted the shape of the artificial tooth by binarizing the image. The separate image data was aligned by detecting the location of the closest number of pixels to the binarized image. Artifacts included in the images were removed manually and the completed voxel data output in DICOM format. Shape was confirmed using free DICOM viewer software（OsiriX）. As a result, the margin of error for superimposing the contour shape of the split image data is approximately one voxel（± 20 μm）. Artifacts were seen in 20 to 50 slices of the binarized images but because they were minor, we were able to process the images quickly and easily. In this study we were able to construct a high-resolution model of artificial teeth with relative ease. In future, if we can success in realizing low-cost, higher performance dental cone-beam CT, we will be able to use it to measure abutment teeth.

学術雑誌論文

Version of Record

0914-7063

AN00229778