| Project/Area Number |
10671946
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | Health Sciences University |
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Principal Investigator |
YOKOYAMA Kazunori Health Sciences University of Hokkaido, Orthodontics, instructor, 歯学部, 講師 (50191515)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Ikue Health Sciences University of Hokkaido, Orthodontics, assistant, 歯学部, 助手 (40260822)
IIJIMA Masahiro Health Sciences University of Hokkaido, Orthodontics, assistant, 歯学部, 助手 (20305915)
YAMAGUCHI Nobuhiko Health Sciences University of Hokkaido, Orthodontics, assistant, 歯学部, 助手 (90285536)
TAKAEUCHI Makoto Health Sciences University of Hokkaido, Orthodontics, instructor, 歯学部, 講師 (00143595)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | cephalogram / oblique cephalogram / three-dimensional reconstruction |
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| Research Abstract |
The authors have developed a method of scanning X-ray photographs and processing their images to reconstruct three-dimensional landmarks in a maxillofacial sttucture from oblique cephalograms for high-precision quantitative measurements.
1. Developing and Improving Three-dimensional Coordinate Reconstniction by Scanner Input
(1)A lead ball was attached to each landmark in a dry skull and each lateral was filled with a root canal filling agent Then oblique (45°right and left), frontal, and lateral cephalograms of the skull were scanned to produce image files using an image scanner After filtering the scanned images using image analysis software, the landmarks at the teeth, skull, and upper and lower maxillary bones were identified manually.
(2)The landmarks were processed in order of horizontal detection, origin migration, and three-dimensional coordinate calculation using a three-dimensional calculation program. Since the difficulty and error of identification at each measuring point diff
… More
er depending on the type of film used, weighting at each landmark was set individually for the four types of photographs and used for the three-dimensional coordinate calculations.
(3)A three-dimensional display program permits free display of the calculated three-dimensional coordinate values from different angles by vertical rotation(±90°), horizontal rotaton(±180°), and parallel translation in the vertical or horizontal direction. The display image can also be enlarged or reduced from 0.62 to 1.61. For comparison before and alter an operation, two three-dimensional coordinate files can be displayed simultaneously in an overlapping form.
(4)Even landmarks difficult to identify from oblique (45°right and left) cephalograms can be identified accurately using frontal, and lateral cephalograms. In addition, lateral coordinate conversion will allow three-dimensional analysis with conventional lateral cephalograms.
2. Application to the Diagnosis of Asymmetric Lower Maxilla
The above method will improve the precision of three-dimensional display and linear or angular measurement in actual cases of asymmetric maxilla and serve as an efficient tool for diagnosis and therapeutic planning. Less
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