{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T16:38:26Z","timestamp":1788539906398,"version":"build-2803163510"},"reference-count":27,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2022,11,18]],"date-time":"2022-11-18T00:00:00Z","timestamp":1668729600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We proposed a novel jaw movement tracking method that can measure in six degrees of freedom. The magnetic field generated by a permanent magnet paired with a small, low-power-consumption Hall effect magnetic sensor is used to estimate the relative distance between two objects\u2014in this instance, the lower and upper jaws. By installing a microelectromechanical system (MEMS) orientation sensor in the device, we developed a mouthpiece-type sensing device that can measure voluntary mandibular movements in three-dimensional orientation and position. An evaluation of individuals wearing this device demonstrated its ability to measure mandibular movement with an accuracy of approximately 3 mm. Using the movement recording feature with six degrees of freedom also enabled the evaluation of an individual\u2019s jaw movements over time in three dimensions. In this method, all sensors are built onto the mouthpiece and the sensing is completed in the oral cavity. It does not require the fixation of a large-scale device to the head or of a jig to the teeth, unlike existing mandibular movement tracking devices. These novel features are expected to increase the accessibility of routine measurements of natural jaw movement, unrestricted by an individual\u2019s physiological movement and posture.<\/jats:p>","DOI":"10.3390\/s22228923","type":"journal-article","created":{"date-parts":[[2022,11,18]],"date-time":"2022-11-18T06:22:28Z","timestamp":1668752548000},"page":"8923","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["A New Intraoral Six-Degrees-of-Freedom Jaw Movement Tracking Method Using Magnetic Fingerprints"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1188-4871","authenticated-orcid":false,"given":"Kinta","family":"Morikawa","sequence":"first","affiliation":[{"name":"Department of Orthodontics, School of Dentistry, Showa University, 2-1-1 Kitasenzoku, Ota-ku, Tokyo 145-8515, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ryosuke","family":"Isogai","sequence":"additional","affiliation":[{"name":"Research and Development Department, Seiko Holdings Corporation, 563, Takatsukashinden, Chiba 270-2222, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junya","family":"Nonaka","sequence":"additional","affiliation":[{"name":"Research and Development Department, Seiko Holdings Corporation, 563, Takatsukashinden, Chiba 270-2222, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yoshifumi","family":"Yoshida","sequence":"additional","affiliation":[{"name":"Research and Development Department, Seiko Holdings Corporation, 563, Takatsukashinden, Chiba 270-2222, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0676-7125","authenticated-orcid":false,"given":"Shugo","family":"Haga","sequence":"additional","affiliation":[{"name":"Department of Orthodontics, School of Dentistry, Showa University, 2-1-1 Kitasenzoku, Ota-ku, Tokyo 145-8515, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Koutaro","family":"Maki","sequence":"additional","affiliation":[{"name":"Department of Orthodontics, School of Dentistry, Showa University, 2-1-1 Kitasenzoku, Ota-ku, Tokyo 145-8515, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"604","DOI":"10.1016\/0022-3913(71)90085-0","article-title":"Functional movements of the mandible","volume":"26","author":"Gibbs","year":"1971","journal-title":"J. Prosthet. Dent."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"311","DOI":"10.1002\/ca.20756","article-title":"Translation and rotation movements of the mandible during mouth opening and closing","volume":"22","author":"Mapelli","year":"2009","journal-title":"Clin. Anat."},{"key":"ref_3","unstructured":"Okeson, J.P. (2003). Management of Temporomandibular Disorders and Occlusion, Elsevier Inc.. [5th ed.]."},{"key":"ref_4","first-page":"378","article-title":"Diagnosis and treatment of temporomandibular disorders","volume":"91","author":"Gauer","year":"2015","journal-title":"Am. Fam. Physician"},{"key":"ref_5","unstructured":"(2022, September 28). K7 Evaluation System. Available online: https:\/\/www.myotronics.com\/k7x."},{"key":"ref_6","unstructured":"(2022, September 28). Gnatho-Hexagraph II (No Longer Commercially Available). (In Chinese)."},{"key":"ref_7","unstructured":"(2022, September 29). WinJMA System. (In German)."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Woodford, S.C., Robinson, D.L., Mehl, A., Lee, P.V.S., and Ackland, D.C. (2020). Measurement of normal and pathological mandibular and temporomandibular joint kinematics: A systematic review. J. Biomech., 111.","DOI":"10.1016\/j.jbiomech.2020.109994"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"573","DOI":"10.1016\/S0021-9290(01)00233-0","article-title":"A simple and inexpensive system for monitoring jaw movements in ambulatory humans","volume":"35","author":"Flavel","year":"2002","journal-title":"J. Biomech."},{"key":"ref_10","first-page":"19905","article-title":"Determination of mandibular border and functional movement protocols using an electromagnetic articulograph (EMA)","volume":"8","author":"Fuentes","year":"2015","journal-title":"Int. J. Clin. Exp. Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"691","DOI":"10.1111\/j.1365-2842.1997.tb01082.x","article-title":"Study of jaw movement and masticatory muscle activity during unilateral chewing with and without balancing side molar contacts","volume":"24","author":"Nishigawa","year":"1997","journal-title":"J. Oral Rehabil."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Jucevi\u010dius, M., O\u017ei\u016bnas, R., Ma\u017eeika, M., Marozas, V., and Jegelevi\u010dius, D. (2021). Accelerometry-enhanced magnetic sensor for intra-oral continuous jaw motion tracking. Sensors, 21.","DOI":"10.3390\/s21041409"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1938","DOI":"10.1109\/20.951014","article-title":"A new method for magnetic position and orientation tracking","volume":"37","author":"Paperno","year":"2001","journal-title":"IEEE Trans Magn."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Singh, M., Shankar, R.A., and Jung, B. (2020, January 25\u201328). Magnetic position tracking using inductor coils and IMU. Proceedings of the 2020 IEEE Sensors, Rotterdam, The Netherlands.","DOI":"10.1109\/SENSORS47125.2020.9278585"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Shao, W., Zhao, F., Wang, C., Luo, H., Muhammad Zahid, T., Wang, Q., and Li, D. (2016). Location fingerprint extraction for magnetic field magnitude based indoor positioning. J. Sens., 2016.","DOI":"10.1155\/2016\/1945695"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"17168","DOI":"10.3390\/s150717168","article-title":"MagicFinger: 3D magnetic fingerprints for indoor location","volume":"15","author":"Carrillo","year":"2015","journal-title":"Sensors"},{"key":"ref_17","unstructured":"(2022, September 28). Numerical Calculation Library for Convex Hull, Qhull. Available online: http:\/\/www.qhull.org."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Nakai, T. (2022). A Uniform magnetic field generator combined with a thin-film magneto-impedance sensor capable of human body scans. Sensors, 22.","DOI":"10.3390\/s22093120"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Masaki, R., Tsuchida, K., Aoyama, H., Honkura, Y., Hayashi, T., Fujii, Y., and Kohno, S. (2005, January 4\u20138). Development of a jaw-position measuring system using magneto-impedance (MI) sensor. Proceedings of the IEEE International Magnetics Conference (INTERMAG), Nagoya, Japan.","DOI":"10.1109\/INTMAG.2005.1464064"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Khan, M.A., Sun, J., Li, B., Przybysz, A., and Kosel, J. (2021). Magnetic sensors-A review and recent technologies. Eng. Res. Express, 3.","DOI":"10.1088\/2631-8695\/ac0838"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"811","DOI":"10.1111\/cid.12163","article-title":"No evidence of genotoxic damage in a group of patients with titanium dental implants and different metal restorations in the oral cavity","volume":"17","year":"2015","journal-title":"Clin. Implant. Dent. Relat. Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"608","DOI":"10.4012\/dmj.2021-330","article-title":"Visualization of orthodontic forces generated by aligner-type appliances","volume":"41","author":"Shimada","year":"2022","journal-title":"Dent. Mater. J."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"592","DOI":"10.1046\/j.1365-2842.2003.01042.x","article-title":"Mandibular condyle movement during mastication of foods","volume":"30","author":"Komiyama","year":"2003","journal-title":"J. Oral Rehabil."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"344","DOI":"10.1016\/j.aanat.2008.04.005","article-title":"Comparison of maximum mouth-opening capacity and condylar path length in adults and children during the growth period","volume":"190","author":"Reicheneder","year":"2008","journal-title":"Ann. Anat."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"567","DOI":"10.5664\/jcsm.4706","article-title":"Mandibular movements identify respiratory effort in pediatric obstructive sleep apnea","volume":"11","author":"Martinot","year":"2015","journal-title":"J. Clin. Sleep Med."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1023\/A:1022931915709","article-title":"Testing the cytotoxicity of metal alloys used as magnetic prosthetic devices","volume":"14","author":"Hopp","year":"2003","journal-title":"J. Mater. Sci. Mater. Med."},{"key":"ref_27","first-page":"118","article-title":"Development of a new intraoral sensing system for measuring the wearing time of clear aligner","volume":"11","author":"Shiotsu","year":"2022","journal-title":"J. Jpn. Acad. Digit. Dent."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/22\/8923\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:20:58Z","timestamp":1760145658000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/22\/8923"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,11,18]]},"references-count":27,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2022,11]]}},"alternative-id":["s22228923"],"URL":"https:\/\/doi.org\/10.3390\/s22228923","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,11,18]]}}}