Electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth opening

Abstract 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 L...

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Main Authors: Xiaoyu Lin, Ryota Takaoka, Daisuke Moriguchi, Shion Morioka, You Ueda, Rie Yamamoto, Emi Ono, Shoichi Ishigaki
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:Scientific Reports
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Online Access:https://doi.org/10.1038/s41598-025-97877-5
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author Xiaoyu Lin
Ryota Takaoka
Daisuke Moriguchi
Shion Morioka
You Ueda
Rie Yamamoto
Emi Ono
Shoichi Ishigaki
author_facet Xiaoyu Lin
Ryota Takaoka
Daisuke Moriguchi
Shion Morioka
You Ueda
Rie Yamamoto
Emi Ono
Shoichi Ishigaki
author_sort Xiaoyu Lin
collection DOAJ
description Abstract 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 (< 40 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 (Omax) and maintain the Omax 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 Omax, the DD + M and M groups exhibited significantly higher masseteric potential than the healthy and DD groups (p < .001). Furthermore, the masseteric potential during Omax 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.
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spelling doaj-art-41baf51c251a4e3da3a2c7b5d11ee8212025-08-20T03:05:26ZengNature PortfolioScientific Reports2045-23222025-04-011511910.1038/s41598-025-97877-5Electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth openingXiaoyu Lin0Ryota Takaoka1Daisuke Moriguchi2Shion Morioka3You Ueda4Rie Yamamoto5Emi Ono6Shoichi Ishigaki7Department of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of DentistryDepartment of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of DentistryDepartment of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of DentistryDepartment of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of DentistryDepartment of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of DentistryDepartment of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of DentistryDepartment of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of DentistryDepartment of Fixed Prosthodontics and Orofacial Function, Osaka University Graduate School of DentistryAbstract 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 (< 40 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 (Omax) and maintain the Omax 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 Omax, the DD + M and M groups exhibited significantly higher masseteric potential than the healthy and DD groups (p < .001). Furthermore, the masseteric potential during Omax 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.https://doi.org/10.1038/s41598-025-97877-5Temporomandibular disordersLimited mouth openingElectromyographyMasseter muscleMyofascial pain
spellingShingle Xiaoyu Lin
Ryota Takaoka
Daisuke Moriguchi
Shion Morioka
You Ueda
Rie Yamamoto
Emi Ono
Shoichi Ishigaki
Electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth opening
Scientific Reports
Temporomandibular disorders
Limited mouth opening
Electromyography
Masseter muscle
Myofascial pain
title Electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth opening
title_full Electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth opening
title_fullStr Electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth opening
title_full_unstemmed Electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth opening
title_short Electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth opening
title_sort electromyographic evaluation of masseteric activity during maximum opening in patients with temporomandibular disorders and limited mouth opening
topic Temporomandibular disorders
Limited mouth opening
Electromyography
Masseter muscle
Myofascial pain
url https://doi.org/10.1038/s41598-025-97877-5
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