| Project/Area Number |
16591959
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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 |
補綴理工系歯学
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| Research Institution | Nagasaki University |
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Principal Investigator |
YAMABE Yoshihisa Nagasaki University, Graduate School of Biomedical Sciences, Associate Professor, 大学院・医歯薬学総合研究科, 助教授 (90191379)
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| Co-Investigator(Kenkyū-buntansha) |
NOGUCHI Kazuko Nagasaki University, Graduate School of Biomedical Sciences, Instructor, 大学院・医歯薬学総合研究科, 助手 (50172771)
TANAKA Mihoko Nagasaki University, Graduate School of Biomedical Sciences, Instructor, 大学院・医歯薬学総合研究科, 助手 (00304957)
小池 麻里 長崎大学, 大学院・医歯薬学総合研究科, 助手 (00234667)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2005: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2004: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Hardness of bite object / Occlusal Force / Mandibular kinesiograph / Motor control / Jaw gape / タッピング力 |
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| Research Abstract |
First, we investigated the modulation of occlusal force to unexpected changes in the occlusal vertical dimension. Using a device to change the vertical jaw closing position, eight healthy subjects were instructed to perform repetitive jaw open-close movements with constant occlusal force. The peak occlusal force was greater in the first trial than that in the second or third trial after increase in the vertical jaw closing position, but it was smaller in the first trial than in the second trial after a decrease in the vertical jaw closing position. The results indicate that this modulation appears to be almost completed in first two or three trials after change in the vertical jaw closing position (Tanaka et al. 2006).
Next, we analyzed the control of occlusal force by experimentally reproducing situations in which the hardness of food changed unpredictably during mastication. Seven healthy subjects were instructed to perform repetitive jaw open-close movements and to maintain constant occlusal force throughout the trial. Peak occlusal force and impulse were significantly affected by the change in hardness, while an increase in hardness caused increase in the values for peak occlusal force and impulse against the instruction, after which those values remained constant while the subjects occlude the same level of hardness. These results indicate that the level of the resulting occlusal force is regulated automatically according to the hardness of the chewed food. We concluded that occlusal force was adopted for efficient mastication when the hardness the hardness of food changes unpredictably (Shimada et al. in press).
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