Evaluation of masseter oxygenation dynamics during wakefulness and sleep bruxism

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K09700
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 57050:Prosthodontics-related
• Research Institution: The University of Tokushima
• Principal Investigator: OKURA Kazuo 徳島大学, 病院, 講師 (70304540)
• Co-Investigator(Kenkyū-buntansha): 鈴木 善貴 徳島大学, 病院, 講師 (40581393) ; 安陪 晋 徳島大学, 大学院医歯薬学研究部(歯学域), 講師 (10359911) ; 松香 芳三 徳島大学, 大学院医歯薬学研究部(歯学域), 教授 (90243477)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 近赤外線組織酸素モニタ / ブラキシズム / 咀嚼筋筋電図 / 筋酸素化動態 / NIRS / クレンチング

Outline of Final Research Achievements

Awake and sleep bruxism is caused by excessive muscle activity, which adversely affects the stomatognathic system, but also causes fatigue and pain in the muscles themselves. In this study, we used a near-infrared tissue oxygen monitor (NIRS) that can measure muscle oxygenation dynamics non-invasively in addition to the conventional evaluation of muscle activity by electromyography, during bruxism and during recovery. The condition of the masseter muscle was examined. We performed tasks assuming bruxism during awakening and measured 　polysomnographs for bruxism during sleep. With continuous clenching, muscle oxygen saturation and oxygenated hemoglobin concentration during the task decreased, and oxygenated hemoglobin concentration increased. Sustained and rhythmic exercise gradually returned to baseline during the recovery period.

Free Research Field

歯科補綴学

Academic Significance and Societal Importance of the Research Achievements

覚醒時ならびに睡眠時ブラキシズムに関して、従来行われてきた筋電図による筋活動の評価のみならず、非侵襲的に筋酸素化動態を測定可能な近赤外線組織酸素モニタ装置（NIRS）を用いて、ブラキシズム中ならびに回復時の咬筋の状態を検討した。筋酸素化動態を確認することで筋電図だけでは把握が困難であった疲労の評価に新たな検討事項を加えることができた。タスク中の筋酸素飽和度と酸素化ヘモグロビン濃度は低下し、脱酸素化ヘモグロビン濃度は上昇した。持続的な運動、リズミカルな運動はともに回復期間中に徐々にベースラインへ回帰していた。NIRSは遮光等に工夫が必要であるが、疲労の詳細な評価項目として重要と考えられた。