2022 Fiscal Year Final Research Report
Masticatory muscle fatigue observed by muscle function magnetic resonance imaging and electromyogram in jaw deformity patients
| Project/Area Number |
20K18787
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 57070:Developmental dentistry-related
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| Research Institution | Kyushu University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | 筋疲労 / 筋機能 MRI / 31P-MRS |
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| Outline of Final Research Achievements |
The transverse relaxation time of muscle functional magnetic resonance imaging , and 31P-magnetic resonance spectroscopy were used to investigate the reliability as parameters for measuring the masseter muscle in patients with skeletal mandibular prognathism. The subjects were 19 patients diagnosed as skeletal mandibular protrusions and 19 healthy subjects as a control group. Transverse relaxation time determined by mfMRI along with creatine phosphate and inorganic phosphorus determined by 31P-MRS before, during, and after clenching were used for molecular imaging of muscle fatigue. The average T2 value of the patient group was significantly higher than that of the healthy control group at rest. Furthermore, the average T2 value transiently increased in both groups during experimental clenching. The pH in the masseter muscle of the patient group was significantly lower than that in the healthy control group at rest and recovery.
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| Free Research Field |
矯正歯科
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| Academic Significance and Societal Importance of the Research Achievements |
筋疲労は、最大筋力の低下もしくは最大収縮速度の低下と定義されており、咬筋、側頭筋を主とした咀嚼筋の疲労や痛みは開口障害や咀嚼障害、慢性疼痛を引き起こし、生活の質の向上に大きく影響していると認識されている。これまで、骨格筋疲労の評価のゴールドスタンダードは、筋表層の活動電位を高い時間分解能で記録できる表面筋電図であるとされてきた。しかしながら、針電極を用いた深層の筋の記録は侵襲的であり、筋全体の活動の記録を行うのは量的に限界があるなどといった問題点も指摘されてきた。しかしながら、今研究結果より筋機能 MRI および 31P-MRS は咬筋の筋疲労の評価の診断法として有効であることが示唆された。
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