| Project/Area Number |
06454033
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
人類学(含生理人類学)
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| Research Institution | Nihon University |
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Principal Investigator |
KANAZAWA Eisaku Nihon University School of Dentistry at Matsudo, Department of Anatomy, 松戸歯学部, 教授 (70050648)
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| Co-Investigator(Kenkyū-buntansha) |
KASAI Kazutaka Nihon University School of Dentistry at Matsudo, Department of Orthodontics, 松戸歯学部, 専任講師 (30169396)
名取 真人 日本大学, 松戸歯学部, 講師 (30189188)
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| Project Period (FY) |
1994 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥6,900,000 (Direct Cost: ¥6,900,000)
Fiscal Year 1996: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1995: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | Occlusion / molar / 3-D measurement / simulation / anthropology / attrition / restoration / Jomonese / 三次元計測 / 進化 / 歯 / レーザー計測 |
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| Research Abstract |
This research is two fold. One is on the restoration of the occlusion analyzed by the 3-D measurement of molars, and the other is the investigation of the types of occlusion in various populations based on the observation of the mandible and teeth of fossil and extant hominoids.
based on the observation of the mandible and teeth of fossil and extant hominoids.
(1) Human molars have three-dimensionally complicated structures. Mechanism of occlusion of a certain population can be traced by the measurement of these structures. This research deals with fossil human molars without attrition with the use of laser 3-D measurement system (Kashimura Co.Ltd.) There is a basic difference of the positional design of cusps between hominoids and anthropoid apes. Modern humans have relatively small teeth but high cusps in the homo lineage. Occlusal table proper is larger than other hominoids. Restoration of the molar crown from the heavily worn molar was tried with the use of 3-D morphing technique. Three-dimensional coordinates of the 49 (7X7) nodes of the matrix were given to the worn molar crown and the sufficient results were obtained.
(2) Bony structures lie on the basement of occlusion. The mandibles of Jomon people, ancestors of modern Japanese from BC 10,000 to 300, were analyzed by the CT scanning. Buccal cortical bone was thick in this population. This implies large vector or force working on the teeth from lingual to buccal side. Heavy attrition in this population is also explained by this directional force. Type of occlusion were also investigated in the South Pacific populations who are thought to have idealistic occlusion among modern humans. Results suggested that edge-to-edge occlusion was popular in Melanesian population and that the type of occlusion in Micronesians was similar to Japanese one.
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