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Title: 長時間連続の律動性咀嚼筋筋活動を認めた覚醒時ブラキシズムの一例
Other Titles: A case of awake bruxism with long-lasting rhythmic masticatory muscle activity
Authors: 山田, 恭子1 Browse this author →KAKEN DB
山口, 泰彦2 Browse this author →KAKEN DB
Authors(alt): Yamada, Kyoko1
Yamaguchi, Taihiko2
Keywords: 覚醒時ブラキシズム
awake bruxism
rhythmic masticatory muscle activity
sleep bruxism
wearable electromyographic device
Issue Date: 15-Sep-2023
Publisher: 北海道歯学会
Journal Title: 北海道歯学雑誌
Volume: 44
Start Page: 87
End Page: 95
Abstract: 【目的】持続時間の短いphasic波形が連なる律動性咀嚼筋筋活動(rhythmic masticatory muscle activity,RMMA)はグラインディングタイプの睡眠時ブラキシズム(sleep bruxism,SB)の筋電図において特徴的とされるが,しかし,日中覚醒時ブラキシズム(awake bruxism,AB)においてSBのような連続性のRMMAが見られることについての報告はなかった.我々は,ABにおいて長時間連続するRMMAを示した症例を経験したので報告する. 【症例】患者は初診時60歳代の女性.前医にて左側顎関節症(非復位性顎関節円板障害)治療後に全顎的な補綴治療が必要な状態であったが,転居のため紹介にて本院に転院し,全顎的に補綴治療を受けた.定期経過観察中の初診7 年後に1|2 の動揺と3 のファイバーポストコアの破折が発現し,③ 2 ① ブリッジと上下顎義歯を新製した.新製後は睡眠時にも臼歯部の咬合支持が必要と考え,睡眠時の義歯装着にて対応していた.しかし,その後も上顎前歯部の動揺が完全には治まらず,初診9 年後にSBとの関連を疑い夜間は義歯だけではなく床付きアプライアンスの装着を検討することとし,事前にSB診断のために睡眠時咬筋筋電図検査を行った.また,ABの可能性も考えられたため,就寝前と起床後の覚醒時間帯も測定した. 【結果】睡眠時はSBのエピソード数は3.7回/hと少なく,睡眠時ブラキサーの基準値以下であった.一方,覚醒時は54.1回/hと多く,しかも波形の大部分が典型的なRMMAであった. 【結論】 睡眠時の咀嚼筋筋活動は正常範囲でも,日中覚醒時に著しい筋活動を示す患者が存在すること,また,日中覚醒時でも長時間連続のRMMAを呈す場合があり得ることが示された.
Purpose: Rhythmic masticatory muscle activity (RMMA), a series of phasic bursts  with short duration , is anelectromyographic (EMG) characteristic of grinding-type sleep bruxism (SB). There have been no reports of long-lasting RMMA regarding awake bruxism (AB), like SB. In this article, we present an AB case with a long-lasting RMMA. Case: This paper reports a case of a woman in her 60s with previously treated temporomandibular disorder (TMD) on the left side (anterior displacement of the temporomandibular joint [TMJ] disc without reduction) who visited our clinic for her relocation and underwent full mouth reconstruction. At a routine follow-up 7 years after the first visit, the anterior maxillary teeth were increasingly mobile, and the fiber post-core of the right maxillary canine tooth, an abutment of a fixed bridge, was found fractured. Subsequently, a maxillary fixed bridge and upper and lower partial dentures were remade. She was instructed to wear the dentures to maintain the occlusal support of the molars during sleep, besides during the daytime. However, even after following the instruction, the mobility of the anterior maxillary teeth persisted. Since SB was suspected 9 years after her first visit, we planned the night-time use of an oral appliance with a denture-type structure in the missing tooth area. A masseteric EMG was recorded to diagnose the SB presence precisely before applying the oral appliance. Since the possibility of AB was also considered, EMG during daytime wakefulness before going to bed and getting up was also measured besides during sleep. Results: The number of episodes, i.e., groups of EMG waveforms during sleep, was 3.7/h, which was small and within the normal range. Conversely, the number of episodes during wakeful ness was 54.1/h, which was exceptionally high, and most of the waveforms were typical RMMA. Conclusion: Based on the clinical experience of this patient, some patients can show a significantly large amount of masticatory muscle activity during the daytime even though masticatory muscle activity is within the normal range during sleep. In addition, it was indicated that long-lasting RMMA can occur in AB during the day.
Type: article
Appears in Collections:北海道歯学雑誌 > 第44巻

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