{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T00:41:48Z","timestamp":1791420108760,"version":"4.3.3"},"reference-count":30,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,2,14]],"date-time":"2022-02-14T00:00:00Z","timestamp":1644796800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Dentistry Journal"],"abstract":"<jats:p>The aim of this study was to investigate and compare the leaching of four different clear aligner systems (Invisalign\u00ae, Eon\u00ae, SureSmile\u00ae, and Clarity\u00ae). Three sets of aligners as obtained from the four manufacturers were cut and immersed in glass vials containing ethanol with different solutions. The first was 100% ethanol, the second was 75% ethanol to 25% water, the third was 50% ethanol to water, the fourth was 25% ethanol to 75% water, and the last was 100% water. The samples were incubated for two weeks at 37 \u00b0C. Leached substances were detected by the gas chromatography\u2013mass spectrometry (GC-MS). Eleven different chemical compounds were detected and confirmed. Benzene1,3-bis(1,1-dimethylethyl) was the only compound detected in all four systems at levels of 100% and 75% ethanol. Statistically, insignificant differences were detected among the different systems where leaching was confirmed. Eon\u00ae system was the only material to show statistically significant differences when comparing the number of leached substances among the immersion solution concentrations. The four included systems showed variable degrees of leaching. The lowest amount of leached chemicals was observed in relation to the Invisalign\u00ae system, while the highest number was found in the Eon\u00ae system. None of the included clear aligner systems leached detectable amounts of bisphenol-A (BPA).<\/jats:p>","DOI":"10.3390\/dj10020027","type":"journal-article","created":{"date-parts":[[2022,2,14]],"date-time":"2022-02-14T20:26:42Z","timestamp":1644870402000},"page":"27","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Leaching of Different Clear Aligner Systems: An In Vitro Study"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6530-7041","authenticated-orcid":false,"given":"Aseel","family":"Alhendi","sequence":"first","affiliation":[{"name":"Department of Pediatric Dentistry and Orthodontics, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rita","family":"Khounganian","sequence":"additional","affiliation":[{"name":"Department of Oral Medicine and Diagnostic Sciences, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abdullazez","family":"Almudhi","sequence":"additional","affiliation":[{"name":"Department of Pediatric Dentistry and Orthodontics, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh 11545, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Syed Rizwan","family":"Ahamad","sequence":"additional","affiliation":[{"name":"Central Laboratory, Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Mi, H.-Y., Jing, X., Turng, L.-S., and Peng, X.-F. (2014, January 15). Microcellular injection molding and particulate leaching of thermoplastic polyurethane (TPU) scaffolds. Proceedings of the AIP Conference Proceedings, Nuremberg, Germany.","DOI":"10.1063\/1.4873807"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"649","DOI":"10.1093\/ejo\/21.6.649","article-title":"Structural conformation of in vitro and in vivo aged orthodontic elastomeric modules","volume":"21","author":"Eliades","year":"1999","journal-title":"Eur. J. Orthod."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"58","DOI":"10.1111\/adj.12480","article-title":"Clear aligners in orthodontic treatment","volume":"62","author":"Weir","year":"2017","journal-title":"Aust. Dent. J."},{"key":"ref_4","unstructured":"Align-Technology (2021, July 14). Invisalign\u00ae Clear Aligners. Available online: https:\/\/www.invisalign.com\/the-invisalign-difference\/smarttrack-aligner-material."},{"key":"ref_5","unstructured":"Eon-holdings (2021, July 14). Eon Clear Aligners\u00ae. Available online: https:\/\/eonaligner.com."},{"key":"ref_6","unstructured":"3M (2021, July 14). Clarity\u00ae Aligners. Available online: https:\/\/www.3m.com\/3M\/en_US\/orthodontics-us\/featured-products\/clarity-eos\/."},{"key":"ref_7","unstructured":"Dentsply-Sirona (2021, July 14). SureSmile\u00ae Clear Aligners. Available online: https:\/\/www.dentsplysirona.com\/en\/explore\/orthodontics\/suresmile-aligner.html."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"725","DOI":"10.1016\/j.ajodo.2004.04.021","article-title":"Structural conformation and leaching from in vitro aged and retrieved Invisalign appliances","volume":"126","author":"Schuster","year":"2004","journal-title":"Am. J. Orthod. Dentofac. Orthop."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1016\/S0022-3913(03)00349-4","article-title":"Cytotoxicity of denture base acrylic resins: A literature review","volume":"90","author":"Jorge","year":"2003","journal-title":"J. Prosthet. Dent."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"413","DOI":"10.1016\/j.ajodo.2004.02.015","article-title":"Light-cured or chemically cured orthodontic adhesive resins? A selection based on the degree of cure, monomer leaching, and cytotoxicity","volume":"127","author":"Gioka","year":"2005","journal-title":"Am. J. Orthod. Dentofac. Orthop."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"516","DOI":"10.2319\/081413-600.1","article-title":"An investigation into bisphenol-A leaching from orthodontic materials","volume":"84","author":"Kotyk","year":"2014","journal-title":"Angle Orthod."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1016\/j.ajodo.2006.08.013","article-title":"Assessment of bisphenol-A release from orthodontic adhesives","volume":"131","author":"Eliades","year":"2007","journal-title":"Am. J. Orthod. Dentofac. Orthop."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Hassan, R., Aslam Khan, M.U., Abdullah, A.M., and Abd Razak, S.I. (2021). A review on current trends of polymers in orthodontics: BPA-free and smart materials. Polymers, 13.","DOI":"10.3390\/polym13091409"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Levrini, L., Mangano, A., Margherini, S., Tenconi, C., Vigetti, D., Muollo, R., and Marco Abbate, G. (2016). ATP bioluminometers analysis on the surfaces of removable orthodontic aligners after the use of different cleaning methods. Int. J. Dent., 1\u20136.","DOI":"10.1155\/2016\/5926941"},{"key":"ref_15","first-page":"439","article-title":"Cytotoxic effects of denture base materials on a permanent human oral epithelial cell line and on primary human oral fibroblasts in vitro","volume":"14","author":"Huang","year":"2001","journal-title":"Int. J. Prosthodont."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"582","DOI":"10.4103\/0970-9290.176919","article-title":"Analysis of adverse events with use of orthodontic sequential aligners as reported in the manufacturer and user facility device experience database","volume":"26","author":"Thavarajah","year":"2015","journal-title":"Indian J. Dent. Res."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"618","DOI":"10.1016\/0022-3913(94)90448-0","article-title":"Leaching and cytotoxicity of formaldehyde and methyl methacrylate from acrylic resin denture base materials","volume":"71","author":"Tsuchiya","year":"1994","journal-title":"J. Prosthet. Dent."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"103239","DOI":"10.1016\/j.etap.2019.103239","article-title":"Impacts of plastic products used in daily life on the environment and human health: What is known?","volume":"72","author":"Rodrigues","year":"2019","journal-title":"Environ. Toxicol. Pharmacol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"471","DOI":"10.1016\/j.ajodo.2016.07.022","article-title":"Comparative evaluation of salivary bisphenol A levels in patients wearing vacuum-formed and Hawley retainers: An in-vivo study","volume":"151","author":"Raghavan","year":"2017","journal-title":"Am. J. Orthod. Dentofac. Orthop."},{"key":"ref_20","unstructured":"WHO, and FAO (2010). Toxicological and Health Aspects of Bisphenol A, FAO."},{"key":"ref_21","unstructured":"NIST (2021, November 23). National Institute of Standard and Technology, Available online: https:\/\/www.nist.gov."},{"key":"ref_22","first-page":"1518","article-title":"Leaching from thermoplastic sheets-a quantitative assessment","volume":"3","author":"Walele","year":"2016","journal-title":"Int. J. Contemp. Med."},{"key":"ref_23","unstructured":"CDC (2021, November 26). Facts about Benzene, Available online: https:\/\/emergency.cdc.gov\/agent\/benzene\/basics\/facts.asp."},{"key":"ref_24","unstructured":"PubChem (2021, October 17). National Library of Medicine, Available online: https:\/\/pubchem.ncbi.nlm.nih.gov."},{"key":"ref_25","unstructured":"ChEBI (2021, November 23). Chemical Entities of Biological Interest. Available online: https:\/\/www.ebi.ac.uk\/chebi\/init.do."},{"key":"ref_26","first-page":"65","article-title":"Chemical composition and general toxicity of essential oils extracted from the aerial parts of Artemisia armeniaca Lam. and A. incana (L.) Druce growing in Iran","volume":"8","author":"Mojarrab","year":"2013","journal-title":"Res. Pharm. Sci."},{"key":"ref_27","first-page":"735","article-title":"Antioxidant effects of quinoline alkaloids and 2,4-Di-tert-butylphenol isolated from Scolopendra subspinipes","volume":"29","author":"Yoon","year":"2006","journal-title":"J. Pharm. Soc. Jpn."},{"key":"ref_28","first-page":"383","article-title":"Assessing the bioactive constituents of Cadaba fruticosa (L.) Druce through GC-MS","volume":"6","author":"Amudha","year":"2014","journal-title":"Int. J. Pharm."},{"key":"ref_29","unstructured":"(2021, November 26). Material Safety Data Sheet. Available online: https:\/\/fscimage.fishersci.com\/msds\/64655.htm."},{"key":"ref_30","first-page":"157","article-title":"Screening orthodontic polymers for leaching","volume":"4","author":"Matasa","year":"2003","journal-title":"World J. Orthod."}],"container-title":["Dentistry Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2304-6767\/10\/2\/27\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:19:12Z","timestamp":1760134752000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2304-6767\/10\/2\/27"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,2,14]]},"references-count":30,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2022,2]]}},"alternative-id":["dj10020027"],"URL":"https:\/\/doi.org\/10.3390\/dj10020027","relation":{},"ISSN":["2304-6767"],"issn-type":[{"value":"2304-6767","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,2,14]]}}}