| Project/Area Number |
05671728
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
矯正・小児・社会系歯学
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| Research Institution | Asahi University |
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Principal Investigator |
TAMURA Yasuo School of Dentistry, Asahi University, Associate professor, 歯学部, 助教授 (40113047)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Shinobu School of Dentistry, Asahi University, Assistant, 歯学部, 助手 (50278206)
SHINODA Keiji School of Dentistry, Asahi University, Assistant, 歯学部, 助手 (30206106)
笹井 浩司 朝日大学, 歯学部, 助手 (90170662)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1994: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Forced crossbite / Mandibular deviation / Masticatory muscle / Electromyogram / Asymmetry Index / Children / 機能的反対咬合 / 非対性正指数 |
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| Research Abstract |
The purpose of the study was to investigate the influence of the mandibular lateral deviation due to the forced crossbites on the masticatory muscles in children. Electromyographic examinations for the masticatory muscles in the children with the mixed dentition with the forced crossbites were performed both during chewing movements (Experiment 1, n=29) and submaximal clenching at the intercuspal position (ICP,Experiment 2, n=15).
1.Differentiation in function of the masticatory muscles due to development, in terms of the temporal vs.masseter muscles, and the working vs.nonworking sides, were found in the normal children during chewing, but those changes were not recognized in the children with the forced crossbites.
2.The mandible was deviated laterally to the side with the forced crossbites from the RCP to the ICP in all subjects. The activity of the temporal muscle during clenching in the ICP tended to be more dominant in the side of the mandible deviated than the other side. When the pattern was classified according to the mandibular deviation and the dominant side in the activity of the masticatory muscles conbined, then subjects were classified into 4 groups from the type I to IV.The type I : the temporal muscle was dominant in muscle activity in the deviated side and the masseter was dominant in the other side, and the type II : the temporal and masseter muscles were dominant in the deviated side, showed the high frequency of 46.7% and 39.3%, respectively.
The present study suggests that the physiological normal development of the masticatory muscles is affected by the the forced crossbites and the mandibular lateral deviation due to the forced crossbites acts on the symmetry of the temporal and masseter muscles activity in children.
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