{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,7]],"date-time":"2026-05-07T05:10:09Z","timestamp":1778130609094,"version":"3.51.4"},"reference-count":32,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,4,26]],"date-time":"2026-04-26T00:00:00Z","timestamp":1777161600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Objectives: This study aimed to analyze longitudinal changes in masticatory muscle volume at pretreatment and after orthognathic surgery in skeletal Class III patients with and without facial asymmetry. Methods: Patients were divided into symmetry and asymmetry groups (n = 30, each; male: female ratio 1: 1, for both groups; age at T1: asymmetry group 25.4 \u00b1 8.1, symmetry group 22.9 \u00b1 7.7). Computed tomography images were obtained at pretreatment (T1), one month after surgery (T2), and at 22 months postoperatively (T3). Three-dimensional reconstruction software was used to measure the volumes of the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles. Results: At T1, the asymmetry group exhibited significantly smaller masseter and temporalis muscle volumes on the deviated side. These differences tended to decrease at T3. No significant bilateral differences were observed in the medial or lateral pterygoid muscles at each point. Longitudinal analyses showed that temporalis and lateral pterygoid muscle volumes decreased from T1 to T2 and increased from T2 to T3, whereas masseter muscle volume did not have a significantly longitudinal difference and the medial pterygoid muscle volume decreased significantly at T3. Conclusions: In Class III patients with facial asymmetry, pretreatment asymmetry of the masseter and temporalis muscle volumes tended to improve postoperatively as bilateral muscle volume increased.<\/jats:p>","DOI":"10.3390\/jcm15093308","type":"journal-article","created":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T09:55:39Z","timestamp":1777370139000},"page":"3308","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Volume Change of Masticatory Muscles by Skeletal Class III Orthognathic Surgery with and Without Facial Asymmetry: A Cross-Sectional and Longitudinal Study"],"prefix":"10.3390","volume":"15","author":[{"given":"Hidehito","family":"Arima","sequence":"first","affiliation":[{"name":"Department of Orthodontics, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chie","family":"Tachiki","sequence":"additional","affiliation":[{"name":"Department of Orthodontics, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takashi","family":"Takaki","sequence":"additional","affiliation":[{"name":"Department of Oral and Maxillofacial Surgery, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Keiichi","family":"Nishikawa","sequence":"additional","affiliation":[{"name":"Department of Chemistry, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tazuko K.","family":"Goto","sequence":"additional","affiliation":[{"name":"Department of Oral and Maxillofacial Radiology, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kenji","family":"Sueishi","sequence":"additional","affiliation":[{"name":"Department of Orthodontics, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7695-1564","authenticated-orcid":false,"given":"Yasushi","family":"Nishii","sequence":"additional","affiliation":[{"name":"Department of Orthodontics, Tokyo Dental College, 2-9-18 Kandamisaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"461","DOI":"10.1016\/j.tripleo.2004.03.015","article-title":"3D CT evaluation of masseter muscle morphology after setback osteotomy for mandibular prognathism","volume":"98","author":"Katsumata","year":"2004","journal-title":"Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"679","DOI":"10.1016\/j.tripleo.2009.05.042","article-title":"Assessment of ramus, condyle, masseter muscle, and occlusal force before and after sagittal split ra-mus osteotomy in patients with mandibular prognathism","volume":"108","author":"Ueki","year":"2009","journal-title":"Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1016\/j.archoralbio.2011.01.012","article-title":"Masseter muscle thickness three years after surgical correction of class III dentofacial deformity","volume":"56","author":"Trawitzki","year":"2011","journal-title":"Arch. Oral Biol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1765","DOI":"10.1177\/00220345890680120901","article-title":"Comparison of jaw-muscle bite-force cross-sections obtained by means of magnetic resonance imaging and high-resolution CT scanning","volume":"68","author":"Weijs","year":"1989","journal-title":"J. Dent. Res."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1111\/j.1601-6343.2010.01505.x","article-title":"Ultrasonography, lateral cephalometry and 3D imaging of the human masseter muscle","volume":"14","author":"Thoirs","year":"2011","journal-title":"Orthod. Craniofacial Res."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"273","DOI":"10.1016\/j.archoralbio.2007.08.013","article-title":"A comparison of human jaw muscle cross-sectional area and volume in long- and short-face subjects, using MRI","volume":"53","author":"Boom","year":"2008","journal-title":"Arch. Oral Biol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2","DOI":"10.21307\/aoj-2020-107","article-title":"Three-dimensional computed tomographic assessment of mandibular muscles in growing subjects with different vertical facial patterns","volume":"32","author":"Wong","year":"2016","journal-title":"Australas. Orthod. J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1046\/j.1526-4610.2001.111006049.x","article-title":"Migraine and masticatory muscle volume, bite force, and craniofacial morphology","volume":"41","author":"Lamey","year":"2001","journal-title":"Headache"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"804","DOI":"10.1002\/jmri.25223","article-title":"Contribution of each mas-ticatory muscle to the bite force determined by MRI using a novel metal-free bite force gauge and an index of total muscle activity","volume":"44","author":"Takahashi","year":"2016","journal-title":"J. Magn. Reson. Imaging"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"830","DOI":"10.1016\/j.ijom.2025.04.002","article-title":"Retrospective 3D analysis of changes in the masseter muscles and soft tissues following orthognathic surgery for patients with maxillomandibular asymmetry: 12-month CBCT study","volume":"54","author":"Tosun","year":"2025","journal-title":"Int. J. Oral Maxillofac. Surg."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"688","DOI":"10.1097\/SCS.0000000000011246","article-title":"Three-dimensional changes of masseter muscle in patients with class III asymmetry after bimaxillary orthognathic surgery","volume":"36","author":"Zhang","year":"2025","journal-title":"J. Craniofacial Surg."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"552","DOI":"10.1177\/154405910608500614","article-title":"Size and orientation of masticatory muscles in patients with mandibular laterognathism","volume":"85","author":"Goto","year":"2006","journal-title":"J. Dent. Res."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1538","DOI":"10.1016\/j.joms.2006.09.024","article-title":"Relationship between the masticatory muscles and mandibular skeleton in mandibular prognathism with and without asymmetry","volume":"65","author":"Kwon","year":"2007","journal-title":"J. Oral Maxillofac. Surg."},{"key":"ref_14","unstructured":"Park, J.H. (2013). Using 3D-CT to analyze the masseter muscle in facial asymmetry before and after orthognathic surgery. Computed Tomography: New Research, Nova Science Publishers."},{"key":"ref_15","unstructured":"American Association of Oral and Maxillofacial Surgeons (2026, February 26). Criteria for Orthognathic Surgery. Available online: https:\/\/aaoms.org\/wp-content\/uploads\/2025\/01\/ortho_indications.pdf."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1111\/j.1741-2358.1998.00003.x","article-title":"Oro-facial muscles: Internal structure, function and ageing","volume":"15","author":"McComas","year":"1998","journal-title":"Gerodontology"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"644","DOI":"10.1016\/j.adaj.2017.03.001","article-title":"Age- and sex-related differ-ences in masseter size and its role in oral functions","volume":"148","author":"Lin","year":"2017","journal-title":"J. Am. Dent. Assoc."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1111\/j.1741-2358.1993.tb00074.x","article-title":"Changes in human jaw muscles with age and dental state","volume":"10","author":"Newton","year":"1993","journal-title":"Gerodontology"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"788","DOI":"10.1016\/j.ajodo.2017.04.024","article-title":"Comparison of different midsagittal plane configura-tions for evaluating craniofacial asymmetry by expert preference","volume":"152","author":"An","year":"2017","journal-title":"Am. J. Orthod. Dentofac. Orthop."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1139","DOI":"10.1016\/j.ajodo.2016.11.023","article-title":"Relationship between molar occlusion and masticatory movement in lateral deviation of the mandible","volume":"151","author":"Suzuki","year":"2017","journal-title":"Am. J. Orthod. Dentofac. Orthop."},{"key":"ref_21","first-page":"669","article-title":"Anatomical study of deep head muscles in Japanese people. No. 1: Masseter. [Translated from Japanese]","volume":"59","author":"Iwata","year":"1959","journal-title":"J. Tokyo Dent. Coll. Soc."},{"key":"ref_22","first-page":"217","article-title":"Anatomical study of ar-rangement and attachment of the medial pterygoid muscle in Japanese men","volume":"38","author":"Abe","year":"1997","journal-title":"Bull. Tokyo Dent. Coll."},{"key":"ref_23","first-page":"135","article-title":"Investigations of the run and the attachment of the lateral pterygoid muscle in Japanese","volume":"34","author":"Abe","year":"1993","journal-title":"Bull. Tokyo Dent. Coll."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1016\/0030-4220(53)90140-6","article-title":"The temporalis muscle","volume":"6","author":"Batson","year":"1953","journal-title":"Oral Surg. Oral Med. Oral Pathol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"607","DOI":"10.2319\/101105-360","article-title":"Ultrasonographic thickness of the masseter muscle in growing individuals with unilateral crossbite","volume":"77","author":"Kiliaridis","year":"2007","journal-title":"Angle Orthod."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1288","DOI":"10.1097\/SCS.0000000000008322","article-title":"The Effect of Orthognathic Surgery on Changes in Masticatory Muscle Volume in Patients with Facial Asymmetry","volume":"33","author":"Eo","year":"2022","journal-title":"J. Craniofacial Surg."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"742","DOI":"10.1016\/j.ijom.2014.02.005","article-title":"Two-year follow-up of changes in bite force and occlusal contact area after intraoral vertical ramus osteotomy with and without Le Fort I osteotomy","volume":"43","author":"Choi","year":"2014","journal-title":"Int. J. Oral Maxillofac. Surg."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/S0901-5027(89)80013-X","article-title":"The anti-inflammatory effect of organo-heparinoid cream after bilateral mandibular osteotomies","volume":"18","author":"Lund","year":"1989","journal-title":"Int. J. Oral Maxillofac. Surg."},{"key":"ref_29","first-page":"667","article-title":"Masseter muscle changes before and after angle-grinding ostectomy and chin augmentation: Evaluation by ultrasound and X-ray","volume":"13","author":"Zhang","year":"2009","journal-title":"J. Clin. Rehabil. Tissue Eng. Res."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"670","DOI":"10.1097\/SAP.0b013e318194fd90","article-title":"Changes of masseter muscles after mandibular an-gle ostectomy in rhesus monkeys","volume":"63","author":"Zhu","year":"2009","journal-title":"Ann. Plast. Surg."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/j.ajoms.2011.07.009","article-title":"Changes in masticatory functions after surgical orthognathic treatment in patients with jaw deformities: Efficacy of masticatory exercise using chewing gum","volume":"24","author":"Kato","year":"2012","journal-title":"J. Oral Maxillofac. Surg. Med. Pathol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"620","DOI":"10.1053\/joms.2001.23373","article-title":"The relationship between surgical changes in dentofacial morphology and changes in maximum bite force","volume":"59","author":"Throckmorton","year":"2001","journal-title":"J. Oral Maxillofac. Surg."}],"container-title":["Journal of Clinical Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/9\/3308\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,7]],"date-time":"2026-05-07T04:11:40Z","timestamp":1778127100000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2077-0383\/15\/9\/3308"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,26]]},"references-count":32,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["jcm15093308"],"URL":"https:\/\/doi.org\/10.3390\/jcm15093308","relation":{},"ISSN":["2077-0383"],"issn-type":[{"value":"2077-0383","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,26]]}}}