Lin Xiaoyu, Takaoka Ryota, Moriguchi Daisuke, Morioka Shion, Ueda You, Yamamoto Rie, Ono Emi, Ishigaki Shoichi
Department of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of Dentistry, 1-8, Yamadaoka, Suita City, Osaka, 565-0871, Japan.
Sci Rep. 2025 Apr 13;15(1):12743. doi: 10.1038/s41598-025-97877-5.
This study aimed to identify the differences in masseteric activity during maximum mouth opening among healthy volunteers, patients with limited mouth opening (LMO) and myofascial pain, and patients with LMO and disc displacement. Thirty-seven patients with temporomandibular disorders and LMO (< 37 mm) and 27 healthy volunteers participated in this study. Patients were categorized into three groups based on magnetic resonance imaging (MRI) findings and clinical symptoms: disc displacement (DD), disc displacement with myofascial pain (DD + M), and myofascial pain (M). The DD group included pain-free disc patients with displacement patients, excluding those with myofascial pain or arthralgia. After a five-minute relaxation period, the participants were instructed to perform maximum opening (O) and maintain the O position for five seconds, and this was repeated three times. Subsequently, the participants were asked to perform maximum voluntary clenching for five seconds, which was repeated twice. At rest, no significant masseter potential differences were observed among the DD, DD + M, M, and healthy groups (p > .05). However, during O, the DD + M and M groups exhibited significantly higher masseteric potential than the healthy and DD groups (p < .001). Furthermore, the masseteric potential during O correlated with self-reported pain levels on a Visual Analog Scale (VAS). Overall, there are distinct differences in masseteric activity levels between patients with LMO and with or without myofascial pain or disc displacement.
本研究旨在确定健康志愿者、张口受限（LMO）和肌筋膜疼痛患者以及LMO和盘移位患者在最大张口时咬肌活动的差异。37例颞下颌关节紊乱且张口受限（<37mm）的患者和27名健康志愿者参与了本研究。根据磁共振成像（MRI）结果和临床症状将患者分为三组：盘移位（DD）、盘移位伴肌筋膜疼痛（DD+M）和肌筋膜疼痛（M）。DD组包括无疼痛的盘移位患者，不包括有肌筋膜疼痛或关节痛的患者。经过5分钟的放松期后，指导参与者进行最大张口（O）并保持O位5秒，重复3次。随后，要求参与者进行最大自主紧咬5秒，重复2次。在静息状态下，DD组、DD+M组、M组和健康组之间未观察到明显的咬肌电位差异（p>.05）。然而，在O过程中，DD+M组和M组的咬肌电位显著高于健康组和DD组（p<.001）。此外，O过程中的咬肌电位与视觉模拟量表（VAS）上自我报告的疼痛水平相关。总体而言，LMO患者以及伴有或不伴有肌筋膜疼痛或盘移位的患者之间咬肌活动水平存在明显差异。
