{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T23:19:01Z","timestamp":1791847141452,"version":"4.3.4"},"reference-count":51,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,4,28]],"date-time":"2025-04-28T00:00:00Z","timestamp":1745798400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003725","name":"National Research Foundation of Korea (NRF)","doi-asserted-by":"publisher","award":["2021R1F1A1049784"],"award-info":[{"award-number":["2021R1F1A1049784"]}],"id":[{"id":"10.13039\/501100003725","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Toxins"],"abstract":"<jats:p>Botulinum toxin type A (BoNT-A), a potent neurotoxin, is increasingly used to treat myogenic temporomandibular disorders (TMDs); however, the interplay between muscle atrophy and pain relief remains incompletely understood. This pilot study investigated how masseter and temporalis muscle thickness and pain intensity change over 12 weeks following BoNT-A injections in 15 patients (mean age 51.42 years) with myogenic TMD. Muscle thickness was measured via ultrasonography across multiple anatomical positions under both clenching and resting conditions at baseline and at 2, 4, 8, and 12 weeks post-injection. Significant thinning of both muscles occurred within 2 weeks, lasting until 12 weeks, but became less pronounced after the first month. Pain intensity showed parallel decreases, most notably early on, but these reductions were not consistently statistically significant. Correlation analyses revealed no strong persistent association between muscle thickness and pain except for a moderately positive correlation in the anterior temporalis at two weeks (r = 0.61, p = 0.04). BoNT-A induces rapid masticatory muscle atrophy and modest pain relief; however, these outcomes do not coincide. Pain relief was observed earlier than the full development of muscle atrophy and should be considered during TMD pain management.<\/jats:p>","DOI":"10.3390\/toxins17050220","type":"journal-article","created":{"date-parts":[[2025,4,28]],"date-time":"2025-04-28T06:23:32Z","timestamp":1745821412000},"page":"220","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Is There a Correlation Between Masticatory Muscle Thickness and Pain After Botulinum Toxin Injections in Myogenic TMD Patients?: A Pilot Study"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6918-1562","authenticated-orcid":false,"given":"Hye-Ji","family":"Park","sequence":"first","affiliation":[{"name":"Department of Oral Medicine, Kyung Hee University Hospital at Gangdong, Seoul 05278, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1139-6261","authenticated-orcid":false,"given":"Hee-Jin","family":"Kim","sequence":"additional","affiliation":[{"name":"Division in Anatomy and Developmental Biology, Department of Oral Biology, Human Identification Research Institute, BK21 FOUR Project, Yonsei University College of Dentistry, Seoul 03722, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9975-8177","authenticated-orcid":false,"given":"Sung Ok","family":"Hong","sequence":"additional","affiliation":[{"name":"Department of Oral and Maxillofacial Surgery, Kyung Hee University Hospital at Gangdong, Seoul 05278, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,4,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"6","DOI":"10.11607\/jop.1151","article-title":"Diagnostic Criteria for Temporomandibular Disorders (DC\/TMD) for Clinical and Research Applications: Recommendations of the International RDC\/TMD Consortium Network* and Orofacial Pain Special Interest Group\u2020","volume":"28","author":"Schiffman","year":"2014","journal-title":"J. Oral Facial Pain Headache"},{"key":"ref_2","first-page":"378","article-title":"Diagnosis and treatment of temporomandibular disorders","volume":"91","author":"Gauer","year":"2015","journal-title":"Am. Fam. Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1111\/joor.12132","article-title":"Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders","volume":"41","author":"Peck","year":"2014","journal-title":"J. Oral Rehabil."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"S125","DOI":"10.1097\/00002508-200211001-00003","article-title":"Possible mechanisms for the effects of botulinum toxin on pain","volume":"18","author":"Arezzo","year":"2002","journal-title":"Clin. J. Pain"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Matak, I., Bolcskei, K., Bach-Rojecky, L., and Helyes, Z. (2019). Mechanisms of Botulinum Toxin Type A Action on Pain. Toxins, 11.","DOI":"10.3390\/toxins11080459"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Hong, S.O. (2023). Cosmetic Treatment Using Botulinum Toxin in the Oral and Maxillofacial Area: A Narrative Review of Esthetic Techniques. Toxins, 15.","DOI":"10.3390\/toxins15020082"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2996","DOI":"10.2174\/0929867327666200806105024","article-title":"The Mechanisms of Action of Botulinum Toxin Type A in Nociceptive and Neuropathic Pathways in Cancer Pain","volume":"28","author":"Salcedo","year":"2021","journal-title":"Curr. Med. Chem."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Reyes, N., Huang, J.J., Choudhury, A., Pondelis, N., Locatelli, E.V., Felix, E.R., Pattany, P.M., Galor, A., and Moulton, E.A. (2023). Botulinum toxin A decreases neural activity in pain-related brain regions in individuals with chronic ocular pain and photophobia. Front. Neurosci., 17.","DOI":"10.3389\/fnins.2023.1202341"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"11362","DOI":"10.3389\/dyst.2023.11362","article-title":"Pain control due to botulinum toxin therapy in cervical dystonia relates to the sensorimotor integration process","volume":"2","author":"Chen","year":"2023","journal-title":"Dystonia"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1054\/bjps.2000.3526","article-title":"A prospective study of the effect of botulinum toxin A on masseteric muscle hypertrophy with ultrasonographic and electromyographic measurement","volume":"54","author":"To","year":"2001","journal-title":"Br. J. Plast. Surg."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Lee, H.J., Jung, S.J., Kim, S.T., and Kim, H.J. (2021). Ultrasonographic Considerations for Safe and Efficient Botulinum Neurotoxin Injection in Masseteric Hypertrophy. Toxins, 13.","DOI":"10.3390\/toxins13010028"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"de Souza Nobre, B.B., Rezende, L., Barbosa C\u00e2mara-Souza, M., Sanchez-Ayala, A., Blass, R., Carbone, A.C., Manso, A.C., Ernberg, M., Christidis, N., and De la Torre Canales, G. (2024). Exploring botulinum toxin\u2019s impact on masseter hypertrophy: A randomized, triple-blinded clinical trial. Sci. Rep., 14.","DOI":"10.1038\/s41598-024-65395-5"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"271","DOI":"10.17219\/dmp\/145759","article-title":"Effects of botulinum toxin in patients with myofascial pain related to temporomandibular joint disorders: A systematic review","volume":"59","author":"Castillo","year":"2022","journal-title":"Dent. Med. Probl."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Kim, S.R., Chang, M., Kim, A.H., and Kim, S.T. (2023). Effect of Botulinum Toxin on Masticatory Muscle Pain in Patients with Temporomandibular Disorders: A Randomized, Double-Blind, Placebo-Controlled Pilot Study. Toxins, 15.","DOI":"10.3390\/toxins15100597"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Kim, H.-J., Youn, K.-H., Kim, J.-S., Kim, Y.S., Hong, S.O., and Na, J. (2020). Ultrasonographic Anatomy of the Face and Neck for Minimally Invasive Procedures: An Anatomic Guideline for Ultrasonographic-Guided, Springer. [1st ed.].","DOI":"10.1007\/978-981-15-6560-1"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1002\/ca.23337","article-title":"Ultrasonography of the internal architecture of the superficial part of the masseter muscle in vivo","volume":"32","author":"Lee","year":"2019","journal-title":"Clin. Anat."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"555","DOI":"10.1016\/S1474-4422(16)00017-X","article-title":"Safety and efficacy of repeated injections of botulinum toxin A in peripheral neuropathic pain (BOTNEP): A randomised, double-blind, placebo-controlled trial","volume":"15","author":"Attal","year":"2016","journal-title":"Lancet Neurol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"804","DOI":"10.1177\/0333102410364677","article-title":"OnabotulinumtoxinA for treatment of chronic migraine: Results from the double-blind, randomized, placebo-controlled phase of the PREEMPT 2 trial","volume":"30","author":"Diener","year":"2010","journal-title":"Cephalalgia Int. J. Headache"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1186\/1129-2377-15-65","article-title":"Two doses of botulinum toxin type A for the treatment of trigeminal neuralgia: Observation of therapeutic effect from a randomized, double-blind, placebo-controlled trial","volume":"15","author":"Zhang","year":"2014","journal-title":"J. Headache Pain"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"De la Torre Canales, G., C\u00e2mara-Souza, M.B., Poluha, R.L., de Figueredo, O.M.C., Nobre, B.B.S., Ernberg, M., Conti, P.C.R., and Rizzatti-Barbosa, C.M. (2022). Long-Term Effects of a Single Application of Botulinum Toxin Type A in Temporomandibular Myofascial Pain Patients: A Controlled Clinical Trial. Toxins, 14.","DOI":"10.3390\/toxins14110741"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"886","DOI":"10.1111\/joor.13648","article-title":"Effect of botulinum toxin type A on muscular temporomandibular disorder: A systematic review and meta-analysis of randomized controlled trials","volume":"51","author":"Li","year":"2024","journal-title":"J. Oral Rehabil."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Lee, Y.H., Chun, Y.H., Bae, H., Lee, J.W., and Kim, H.J. (2024). Comparison of ultrasonography-based masticatory muscle thickness between temporomandibular disorders bruxers and temporomandibular disorders non-bruxers. Sci. Rep., 14.","DOI":"10.1038\/s41598-024-57696-6"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Maranini, B., Ciancio, G., Mandrioli, S., Galie, M., and Govoni, M. (2022). The Role of Ultrasound in Temporomandibular Joint Disorders: An Update and Future Perspectives. Front. Med., 9.","DOI":"10.3389\/fmed.2022.926573"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.jdsr.2016.05.001","article-title":"Magnetic resonance and sonographic imagings of masticatory muscle myalgia in temporomandibular disorder patients","volume":"53","author":"Ariji","year":"2017","journal-title":"Jpn. Dent. Sci. Rev."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2125","DOI":"10.1111\/joor.13800","article-title":"Comparison between botulinum toxin type A injection on masseter muscle only and additional injection on anterior belly of digastric muscle in sleep bruxism patients: A clinical trial","volume":"51","author":"Kim","year":"2024","journal-title":"J. Oral Rehabil."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Bae, H., Lee, Y.H., Kim, S.B., Hu, K.S., and Kim, H.J. (2024). Ultrasonographic assessment of the lateral pterygoid muscle for BoNT-A injection. Clin. Anat.","DOI":"10.1002\/ca.24220"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1079","DOI":"10.1016\/0003-9969(94)90061-2","article-title":"A comparison of human masseter muscle thickness measured by ultrasonography and magnetic resonance imaging","volume":"39","author":"Raadsheer","year":"1994","journal-title":"Arch. Oral Biol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"707","DOI":"10.2174\/1573405616666201214121557","article-title":"Methods of Masseter and Temporal Muscle Thickness and Elasticity Measurements by Ultrasound Imaging: A Literature Review","volume":"17","author":"Blicharz","year":"2021","journal-title":"Curr. Med. Imaging"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"30","DOI":"10.5935\/0946-5448.20180005","article-title":"Relationship between Otological Symptoms and TMD","volume":"22","author":"Kusdra","year":"2018","journal-title":"Int. Tinnitus J."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Lee, Y.H., Bae, H., Chun, Y.H., Lee, J.W., and Kim, H.J. (2024). Ultrasonographic examination of masticatory muscles in patients with TMJ arthralgia and headache attributed to temporomandibular disorders. Sci. Rep., 14.","DOI":"10.1038\/s41598-024-59316-9"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1100","DOI":"10.1016\/j.archoralbio.2013.04.006","article-title":"Assessment of thickness and function of masticatory and cervical muscles in adults with and without temporomandibular disorders","volume":"58","author":"Strini","year":"2013","journal-title":"Arch. Oral Biol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1686","DOI":"10.1177\/00220345900690101101","article-title":"Electromyographic heterogeneity in the human temporalis muscle","volume":"69","author":"Blanksma","year":"1990","journal-title":"J. Dent. Res."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1693","DOI":"10.1097\/PRS.0b013e3181d0ad03","article-title":"Botulinum toxin type A for the treatment of hypertrophy of the masseter muscle","volume":"125","author":"Kim","year":"2010","journal-title":"Plast. Reconstr. Surg."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1124\/pr.116.012658","article-title":"Botulinum Neurotoxins: Biology, Pharmacology, and Toxicology","volume":"69","author":"Pirazzini","year":"2017","journal-title":"Pharmacol. Rev."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"736","DOI":"10.1016\/j.bjoms.2016.04.008","article-title":"Occlusal force characteristics of masseteric muscles after intramuscular injection of botulinum toxin A(BTX\u2014A)for treatment of temporomandibular disorder","volume":"54","author":"Zhang","year":"2016","journal-title":"Br. J. Oral Maxillofac. Surg."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1014","DOI":"10.1111\/papr.13396","article-title":"Clinical benefit of botulinum toxin for treatment of persistent TMD-related myofascial pain: A randomized, placebo-controlled, cross-over trial","volume":"24","author":"Sitnikova","year":"2024","journal-title":"Pain. Pract."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1016\/j.jpain.2019.08.011","article-title":"Botulinum Toxin Type A for Painful Temporomandibular Disorders: Systematic Review and Meta-Analysis","volume":"21","author":"Machado","year":"2020","journal-title":"J. Pain"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"508","DOI":"10.1016\/j.bjoms.2020.02.007","article-title":"Botulinum toxin in the management of temporomandibular disorders: A systematic review","volume":"58","author":"Thambar","year":"2020","journal-title":"Br. J. Oral Maxillofac. Surg."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Luvisetto, S. (2021). Botulinum Neurotoxins in Central Nervous System: An Overview from Animal Models to Human Therapy. Toxins, 13.","DOI":"10.3390\/toxins13110751"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1002\/ana.21427","article-title":"Botulinum toxin type A induces direct analgesic effects in chronic neuropathic pain","volume":"64","author":"Ranoux","year":"2008","journal-title":"Ann. Neurol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"1988","DOI":"10.1016\/j.pain.2011.03.036","article-title":"Efficacy of botulinum toxin type A for treatment of persistent myofascial TMD pain: A randomized, controlled, double-blind multicenter study","volume":"152","author":"Ernberg","year":"2011","journal-title":"Pain"},{"key":"ref_42","first-page":"421","article-title":"Is low dose of botulinum toxin effective in controlling chronic pain in sleep bruxism, awake bruxism, and temporomandibular disorder?","volume":"42","year":"2024","journal-title":"Cranio J. Craniomandib. Pract."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1136\/jnnp.64.1.13","article-title":"What is the optimal dose of botulinum toxin A in the treatment of cervical dystonia? Results of a double blind, placebo controlled, dose ranging study using Dysport. German Dystonia Study Group","volume":"64","author":"Poewe","year":"1998","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1054\/bjom.1999.0238","article-title":"Botulinum toxin: New treatment for temporomandibular disorders","volume":"38","author":"Freund","year":"2000","journal-title":"Br. J. Oral Maxillofac. Surg."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"1644","DOI":"10.1016\/j.joms.2008.03.008","article-title":"Effect of botulinum toxin-A in myofascial pain patients with or without functional disc displacement","volume":"66","author":"Kurtoglu","year":"2008","journal-title":"J. Oral. Maxillofac. Surg."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"De la Torre Canales, G., Alvarez-Pinzon, N., Mu\u00f1oz-Lora, V.R.M., Vieira Peroni, L., Farias Gomes, A., S\u00e1nchez-Ayala, A., Haiter-Neto, F., Manfredini, D., and Rizzatti-Barbosa, C.M. (2020). Efficacy and Safety of Botulinum Toxin Type A on Persistent Myofascial Pain: A Randomized Clinical Trial. Toxins, 12.","DOI":"10.3390\/toxins12060395"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"4519","DOI":"10.3390\/toxins7114519","article-title":"Current status and future directions of botulinum neurotoxins for targeting pain processing","volume":"7","author":"Pellett","year":"2015","journal-title":"Toxins"},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Montes-Carmona, J.F., Gonzalez-Perez, L.M., and Infante-Cossio, P. (2020). Treatment of Localized and Referred Masticatory Myofascial Pain with Botulinum Toxin Injection. Toxins, 13.","DOI":"10.3390\/toxins13010006"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1186\/s10194-016-0621-1","article-title":"The efficiency of botulinum toxin type A for the treatment of masseter muscle pain in patients with temporomandibular joint dysfunction and tension-type headache","volume":"17","author":"Pihut","year":"2016","journal-title":"J. Headache Pain"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1237","DOI":"10.1007\/s00276-024-03429-3","article-title":"Sonoanatomy of injecting botulinum neurotoxin into the facial muscles","volume":"46","author":"Kim","year":"2024","journal-title":"Surg. Radiol. Anat."},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Bae, H., Kim, J., Seo, K.K., Hu, K.S., Kim, S.T., and Kim, H.J. (2020). Comparison between Conventional Blind Injections and Ultrasound-Guided Injections of Botulinum Toxin Type A into the Masseter: A Clinical Trial. Toxins, 12.","DOI":"10.3390\/toxins12090588"}],"container-title":["Toxins"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6651\/17\/5\/220\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:23:03Z","timestamp":1760030583000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6651\/17\/5\/220"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,28]]},"references-count":51,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2025,5]]}},"alternative-id":["toxins17050220"],"URL":"https:\/\/doi.org\/10.3390\/toxins17050220","relation":{},"ISSN":["2072-6651"],"issn-type":[{"value":"2072-6651","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,4,28]]}}}