1997 Fiscal Year Final Research Report Summary
Electromyographic estimtion of incompetent lip
| Project/Area Number |
08672366
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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 | HIROSHIMA UNIVERSITY |
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Principal Investigator |
YAMAGUCHI Kazunori Hiroshima University, School of Dentistry, Associate Professor, 歯学部, 助教授 (50112214)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Kazue Hiroshima University, Dental hospital, lecturer, 歯学部・附属病院, 講師 (10034208)
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| Project Period (FY) |
1996 – 1997
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| Keywords | incompetent lip / clenching / electromyography / orthognathic surgery / open bite |
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| Research Abstract |
Part 1
Young adult samples consisted of forty nine subjects with positive overjet and overbite, and seventeen with open bite. Two bipolar surface electrodes were attached to the skin of the upper and lower lips. The mean integrated amplitude of the EMG activity at mandibular rest position with the based on positive and negative values of the difference in integrated EMG activity of the mentalis muscle between two lip positions. Subjects who showed negative value was calssified as having competent lips and those with positive value were lip incompetent. The EMG activity of the mentalis muscle was indicative in sealing lips as compared to that of depressor of lower lip. All subjects in the open bite group hadn incompetent lips. The incompetent lips group showed steeper mandibular plane as well as large proclination of maxilary and mandibular incisors than the competent lips group. It was suggested that the difference of the EMG activity of the mentalis muscle at mandibular rest position w
… More
ith the lips in contact and apart offers an objective criterion for the evaluation of lip competence and that vertical dimension of the face as well as proclination of the incisors can affect lower lip function.
Part 2
Sample consisted of forty-nine subjects with positive overjet and overbite, and seventeen skeletal open bite subjects which received orthognathic surgery. EMG recording of lower lip and masticatory muscles was taken at rest and during clenching with the lips in contact and apart. EMG activities of the lower lip and cephalometric measurements were statistically compared between the competent and incompetent lips groups using analysis of variance (ANOVA). EMG activity of the lower lip during clenching with the lips in contact decreased in the incompetent lips subjects but not in the competent lips subjects and it was correlated (r= -0.910, -0.980) with that at rest position in the incompetent lips and open bite groups. It was found that the incompetent lips subjects showed distinct functional coordination between the lower lip and masseter muscle. Less
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