2003 Fiscal Year Final Research Report Summary
ASSOCIATION OF EMG ACTIVITY OF THE LIPS WITH MASTICATORY MUSCLE IN INDIVIDUALS WITH MALOCCLUSION
| Project/Area Number |
14571962
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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 | KYUSHU DENTAL COLLEGE |
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Principal Investigator |
YAMAGUCHI Kazunori KYUSYU DENTAL COLLEGE, SCHOOL OF DENTISTRY, ORTHODONTICS, PROFESSOR, 歯学部, 教授 (50112214)
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| Co-Investigator(Kenkyū-buntansha) |
TAKIGUTI Reiko KYUSYU DENTAL COLLEGE, SCHOL OF DENTISTRY, ORTHODONTICS, ASSISTANT PROFESSOR, 歯学部, 助手 (80128800)
ICHIDA Toshimiti KYUSYU DENTAL COLLEGE, SCHOOL OF DENTISTRY, OTHODONTICS, ASSISTANT PROFESSOR, 歯学部, 助手 (70094761)
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| Project Period (FY) |
2002 – 2003
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| Keywords | LIP SEALING / LOSER LIP / MASSETER MUSCLE / EMG ACTIVITY / INCOMPETENT LIPS / CHEWING |
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| Research Abstract |
In subjects with competent lips, the lips are lightly closed during chewing food. However, in some patients with incompetent lips, the lips are not always closed during masticatory function. Chewing with the lips closed is an involuntary act in both subjects with incompetent lips and competent lips. In contrast, chewing with the lip closed is not a natural act in subjects with incompetent lips. The purpose of this study was to investigate the relationship between activities of lower lip and masticatory muscles.
Results
(1)The amplitudes of EMG activity of lower lip during chewing with lip in contact and apart during masseter active and non-active (tonic) contraction phases were significantly higher in the incompetent lip group than in competent lip group.
(2)The duration of EMG activity during tonic masseter activity with lip contact was shorter in incompetent lip group than in competent lip group.
Our results suggested that failure of lip sealing is probably due to facial morphological disharmony and that such failure also affects the masticatory function.
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