1997 Fiscal Year Final Research Report Summary
Relationship between occlusal obnormality and symptour of Temporomandibular Disorders
| Project/Area Number |
08672230
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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 | Tokyo Medical and Dental University, Faculty of Dentistry |
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Principal Investigator |
YATABE Masaru Tokyo Medical and Dental University, Faculty of Dentistry, 歯学部, 助手 (10182354)
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| Co-Investigator(Kenkyū-buntansha) |
AKISHIGE Satoshi Tokyo Medical and Dental University, Faculty of Dentistry, 歯学部, 助手 (30272602)
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| Project Period (FY) |
1996 – 1997
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| Keywords | somatization / TMD / occlusion / EMG / clenching / bruxism |
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| Research Abstract |
We conducted two study projects as described below. The purpose of the first study was to identify the profiles of occlusal disharmony associated with psychosomatic aspects in temporomandibular disorder patients. Thirteen female patients (with a mean age of 47.4 years) who complained of occlusal disturbances and/or occlusal instability caused by past dental treatment completed clinical examinations and psychosomatic inventories (CMI,MAS). Clinical examinations included measurements of occlusal contact areas, occlusal forces at 50% of maximal voluntary contraction (MVC), range of tapping points. Relationship among these values were statistically analyzed. There was a significant correlation between psychological aspects and values of occlusal contact area and occlusal force. Tapping points were significantly greater in the anteroposterior range than in the lateral range (p<0.05). Statistically significant correlation were found between manifest anxiety and the lateral range of tapping p
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oints. These results confirm associations between psychosomatic aspects and the occlusal and functional status.
The second study examined the relationship among occlusal contact, the response of muscles, and the jaw displacement during simulated clenching. Seven healthy human males with complete natural dental arches with normal occlusion volunteered for this study. Acylic occlusal stops were fabricated for the lower jaw to simulate various occlusal states. Vertical movement of the lower jaw was measured by four sets of linear variable differential transformers. Simultaneously, electromyographic activity from bilateral masseter and anterior and posterior temporal muscles was measured. Under experimentally altered occlusal conditions, subjects were asked to clench at 50% MVC.Both the EMG activity pattern and the displacement pattern were clearly affected by the site and number of occlusal stops. Clenching on bilateral premolar stops caused jaw tipping with a tendency of being elevated more in the posterior region than in the anterior region. When bilateral second molar stops were in place, the upward movement of the posterior region was decreased. Clenching on unilateral stops caused larger upward movement of the jaw on the contralateral side and larger activity in the ipsilateral temporal muscle. It was suggested that the specific occlusal abnormality might provoke specific muscle activity and temporomandibular joint loading during parafunction. Less
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