Nakagawa Yu, Yamaguchi Taihiko, Ishimaru Tomoya, Saito Taishi, Hattori Yoshinori, Ono Takahiro, Arai Yoshiaki, Hasegawa Yoko, Shiga Hiroshi, Tamaki Katsushi, Tanaka Junko, Tsuga Kazuhiro, Abekura Hitoshi, Miyawaki Shouichi, Maeda-Iino Aya, Mikami Saki, Gotouda Akihito, Shimizu Koichi, Kato Yuji, Namita Takeshi, Kuroshima Shinichiro
Department of Crown and Bridge Prosthodontics, Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan.
Faculty of Dental Medicine, Hokkaido University, Sapporo, Japan.
J Oral Rehabil. 2025 Nov;52(11):1922-1932. doi: 10.1111/joor.14050. Epub 2025 Jun 12.
To establish diagnostic/assessment criteria for awake bruxism (AB) using electromyography of the masseter muscle during the diurnal awake state (d-EMG), it is necessary to refer to the actual state of variation of d-EMG waveforms between different days (d-variation).
This study aimed to clarify the actual state of d-variation in various indices of d-EMG waveforms.
The participants included 91 volunteers with or without awareness of diurnal tooth clenching. Measurements were conducted on three days within a two-week period using a wearable EMG device set at the unilateral masseteric region. A waveform with an amplitude more than twice the baseline and a duration of more than 0.25 s was defined as a burst. The number of bursts/h, number of episodes/h, number of bursts ≥ 20% maximum voluntary clenching (MVC)/h, burst integral value/h, and standardised burst integral value/h were calculated. The coefficient of variation (CV) of the three measurement days was calculated for each index.
The five indices showed no significant differences among the three days. The median CV for the number of episodes/h, number of bursts/h, number of bursts ≥ 20% MVC/h, burst integral value/h, and standardised burst integral value/h were 0.233, 0.276, 0.507, 0.417, and 0.482, respectively. Of the indices, bursts/h and episodes/h had the smallest day-to-day variation. The CV for the number of waveforms tended to be smaller the larger the number of waveforms.
These findings are considered useful as reference data for establishing diagnostic/assessment criteria for AB using masseter EMG in the future.
为了利用日间清醒状态下咬肌的肌电图（d - EMG）建立清醒性磨牙症（AB）的诊断/评估标准，有必要参考不同日期之间d - EMG波形变化的实际情况（d - 变化）。
本研究旨在阐明d - EMG波形各项指标的d - 变化实际情况。
参与者包括91名有或无日间紧咬牙意识的志愿者。在两周内的三天使用设置于单侧咬肌区域的可穿戴式肌电图设备进行测量。将振幅超过基线两倍且持续时间超过0.25秒的波形定义为一次爆发。计算每小时的爆发次数、发作次数、≥最大自主紧咬（MVC）20%的爆发次数/小时、爆发积分值/小时以及标准化爆发积分值/小时。计算每个指标在三个测量日的变异系数（CV）。
这五项指标在三天之间无显著差异。每小时发作次数、每小时爆发次数、≥MVC 20%的爆发次数/小时、爆发积分值/小时以及标准化爆发积分值/小时的CV中位数分别为0.233、0.276、0.507、0.417和0.482。在这些指标中，每小时爆发次数和每小时发作次数的每日变化最小。波形数量越多，其CV往往越小。
这些发现被认为可作为未来利用咬肌肌电图建立AB诊断/评估标准的参考数据。
