A Study About Maxillofacial Growth Using ThreeーDimensional Reconstruction and Bone Mineral Measurement Employing X-ray Computed Tomography.

1990 Fiscal Year Final Research Report Summary

• Project/Area Number: 63570971
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 小児・社会系歯学
• Research Institution: Showa University
• Principal Investigator: OHTSUKA Suminasa Showa Univ., Dent., Lecturer, 歯学部, 講師 (80129816)
• Co-Investigator(Kenkyū-buntansha): MAKI KOUTAROU Showa Univ., Dent., Assistant., 歯学部, 助手 (80219295) ; SHIBASAKI YOSHINOBU Showa Univ., Dent., Professor, 歯学部, 教授 (40014005)
• Project Period (FY): 1988 – 1990
• Keywords: Bone density / Three-dimension / Reconstruction / Computed Tomography / Mandible / Ca_<10>(PO_4)_6OH_2 / 三次元再構築 / 骨添加,吸収

Research Abstract

In order to investigate the three-dimensional changes on bone density in maxillofacial skeleton, we developed a new method and external reference phantom. A facial mask was developed with the purpose of scanning same site on a same patient and making the standard for three-dimensional superimposition of several density levels and whole contours. Also a external refence phantom for bone density measurement on maxillofacial skeleton was manufactured from Ca_<10> (PO_4) _6OH_2. The reproducibility of scanning direction was determined with the scanning repeated twice on same target. The accuracy of calibration was tested under the various conditions, which included the target size, position, and filtered functions. From the results of these tests, there is on significant differences existed between two scanned images, and good correlation was seen between the CT number and the Ca density of the phantom rods. Also the accurate three dimensional distribution of bone density was produced by using the facial mask. Bone density values of mandible were calculated for twenty individuals ranging from 6 to 16 years of age according to a mineral equivalent calibration derived from the developed method. Extracted images with the same level of density were reconstructed three-dimensionally. In the normal growth, increase of bone density was found and the higher-density areas were distributed on the buccal and inferior areas of the lingual surface on the mandibular body.