{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T02:13:22Z","timestamp":1760235202793,"version":"build-2065373602"},"reference-count":18,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,7,28]],"date-time":"2021-07-28T00:00:00Z","timestamp":1627430400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Children"],"abstract":"<jats:p>Ectopic eruption of the permanent molar may absorb the distal root of the primary second molar and may result in a decreased arch length or delayed eruption of the permanent tooth, requiring timely treatment. Therefore, we devised an effective and convenient method to unlock the entrapped tooth using a novel device called a \u201cpiston-elastic\u201d. This case report aims to explain the design and clinical application of this piston-elastic and to describe successful cases. Three patients (aged 6, 13, and 16 years) with ectopically erupted maxillary and mandibular molars, respectively, were treated with a piston-elastic. It was bound to the locked molar to improve the eruption path. After a certain time period, the repulsive force pushed the surface of the adjacent tooth, improving the eruption path of the entrapped tooth. The piston-elastic is a novel device that simply and effectively changes the direction of eruption of ectopically entrapped molars. As it can be manufactured and attached to the chair side, impression acquisition on a model cast and laboratory procedures are unnecessary. Compared to existing methods, the piston-elastic can be easily produced and delivered, causes little irritation, and is inexpensive.<\/jats:p>","DOI":"10.3390\/children8080652","type":"journal-article","created":{"date-parts":[[2021,7,28]],"date-time":"2021-07-28T11:12:52Z","timestamp":1627470772000},"page":"652","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["The Piston Elastic: A Novel Device for Treating Entrapped Ectopic Permanent Molars"],"prefix":"10.3390","volume":"8","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4444-532X","authenticated-orcid":false,"given":"Ik-Hwan","family":"Kim","sequence":"first","affiliation":[{"name":"Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7813-3741","authenticated-orcid":false,"given":"Chung-Min","family":"Kang","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8620-5629","authenticated-orcid":false,"given":"Je Seon","family":"Song","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1556-3485","authenticated-orcid":false,"given":"Jaeho","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3315-6912","authenticated-orcid":false,"given":"Hyung-Jun","family":"Choi","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8620-1377","authenticated-orcid":false,"given":"Seong-Oh","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry, College of Dentistry, Yonsei University, Seoul 03722, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2021,7,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"773","DOI":"10.2319\/072506-306.1","article-title":"Prevalence of ectopic eruption, impaction, retention and agenesis of the permanent second molar","volume":"77","author":"Bondemark","year":"2007","journal-title":"Angle Orthod."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1016\/0002-9416(83)90179-3","article-title":"Ectopic eruption of the maxillary first permanent molar: Etiologic factors","volume":"84","author":"Bjerklin","year":"1983","journal-title":"Am. 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Assoc."}],"container-title":["Children"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2227-9067\/8\/8\/652\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:36:27Z","timestamp":1760164587000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2227-9067\/8\/8\/652"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,7,28]]},"references-count":18,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2021,8]]}},"alternative-id":["children8080652"],"URL":"https:\/\/doi.org\/10.3390\/children8080652","relation":{},"ISSN":["2227-9067"],"issn-type":[{"type":"electronic","value":"2227-9067"}],"subject":[],"published":{"date-parts":[[2021,7,28]]}}}