| Project/Area Number |
12470459
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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 |
矯正・小児・社会系歯学
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| Research Institution | Osaka University |
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Principal Investigator |
HIDAKA Osamu Dental Hospital, Osaka University, Assistant Professor, 歯学部・附属病院, 講師 (30252696)
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| Co-Investigator(Kenkyū-buntansha) |
MURAKAMI Shumei Graduate School of Dentistry, Osaka University, Associate Professor, 大学院・歯学研究科, 助教授 (00263301)
FURUKAWA Souhei Graduate School of Dentistry, Osaka University, Professor, 大学院・歯学研究科, 教授 (80173524)
TAKADA Kenji Graduate School of Dentistry, Osaka University, Professor, 大学院・歯学研究科, 教授 (50127247)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥14,100,000 (Direct Cost: ¥14,100,000)
Fiscal Year 2001: ¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 2000: ¥6,500,000 (Direct Cost: ¥6,500,000)
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| Keywords | Stressor / Masticatory muscle EMG / Blood flow / Sweat / Electrocardiogram |
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| Research Abstract |
It has been known empirically that under mental stress, skeletal muscle tone is increased and parafunction such as clenching or teeth grinding can be caused unconsciously, which suggests that a close relationship exists between the stomatognathic system and the mental condition. In this study, therefore, we investigated what the effect of mental stress on the stomatognathic system is and what the effect of occlusal splints is.
Healthy adult volunteers participated in this study. A letter identification task over a 2-hour period was employed as a stressor. Electromyographic records were taken from the temporal and masseteric muscles, sweat rates from the palmar surface of index finger and from forehead, skin blood flow from the palmar surface of index finger, local muscle oxygenation from the masseter muscle. Assessment of autonomic function was made by heart rate spectral analysis. Two occlusal splints of different hardness were employed.
During the mental task, the integrated EMG activity of masseteric and temporal muscles, tissue hemoglobin O_2 saturation (StO_2), and the Lo/Hi ratio (a marker of sympathetic activity) increased as compared before the mental task. These increases were statistically significant after at least 30 to 60 minutes ; afterwards no notable changes were found. The integrated skin blood flow and sweat expulsion did not change significantly. The integrated temporal EMG activity and Lo/Hi ratio increased with the soft splint, but did not with the hard splint. These results indicate that the hardness of an occlusal splint can affect the masticatory muscle activity and autonomic nervous system activity under stressful conditions.
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