{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T14:56:34Z","timestamp":1792421794071,"version":"4.5.0"},"reference-count":39,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,4,5]],"date-time":"2021-04-05T00:00:00Z","timestamp":1617580800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>The recent introduction of three-dimensional (3D) printing is revolutionizing dentistry and is even being applied to orthodontic treatment of malocclusion. Clear, personalized, removable aligners are a suitable alternative to conventional orthodontic appliances, offering a more comfortable and efficient solution for patients. Including improved oral hygiene and aesthetics during treatment. Contemporarily, clear aligners are produced by a thermoforming process using various types of thermoplastic materials. The thermoforming procedure alters the properties of the material, and the intraoral environment further modifies the properties of a clear aligner, affecting overall performance of the material. Direct 3D printing offers the creation of highly precise clear aligners with soft edges, digitally designed and identically reproduced for an entire set of treatment aligners; offering a better fit, higher efficacy, and reproducibility. Despite the known benefits of 3D printing and the popularity of its dental applications, very limited technical and clinical data are available in the literature about directly printed clear aligners. The present article discusses the advantages of 3D printed aligners in comparison to thermoformed ones, describes the current state of the art, including a discussion of the possible road blocks that exist such as a current lack of approved and marketed materials and limited existence of aligner specific software. The present review suggests the suitability of 3D direct printed aligners is superior to that of thermoformed manufactured aligners because of the prior\u2019s increased accuracy, load resistance, and lower deformation. It is an overall more stable way to produce an aligner where submillimeter movements can make a difference in treatment outcome. Direct 3D printing represents a complex method to control the thickness of the aligner and therefore has a better ability to control the force vectors that are used to produce tooth movement. There is currently no other approved material on the market that can do this. The conclusion of this article is that we encourage further in vitro and in vivo studies to test these new technologies and materials.<\/jats:p>","DOI":"10.3390\/ma14071799","type":"journal-article","created":{"date-parts":[[2021,4,5]],"date-time":"2021-04-05T11:48:29Z","timestamp":1617623309000},"page":"1799","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":277,"title":["Direct 3D Printing of Clear Orthodontic Aligners: Current State and Future Possibilities"],"prefix":"10.3390","volume":"14","author":[{"given":"Gianluca M.","family":"Tartaglia","sequence":"first","affiliation":[{"name":"Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, University of Milan, 20100 Milan, Italy"},{"name":"Fondazione IRCCS C\u00e0 Granda, Ospedale Maggiore Policlinico, 20100 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrea","family":"Mapelli","sequence":"additional","affiliation":[{"name":"Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, University of Milan, 20100 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5930-1698","authenticated-orcid":false,"given":"Cinzia","family":"Maspero","sequence":"additional","affiliation":[{"name":"Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, University of Milan, 20100 Milan, Italy"},{"name":"Fondazione IRCCS C\u00e0 Granda, Ospedale Maggiore Policlinico, 20100 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tommaso","family":"Santaniello","sequence":"additional","affiliation":[{"name":"Department of Physics, University of Milan, 20100 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4680-0989","authenticated-orcid":false,"given":"Marco","family":"Serafin","sequence":"additional","affiliation":[{"name":"Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, University of Milan, 20100 Milan, Italy"},{"name":"Fondazione IRCCS C\u00e0 Granda, Ospedale Maggiore Policlinico, 20100 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6209-9873","authenticated-orcid":false,"given":"Marco","family":"Farronato","sequence":"additional","affiliation":[{"name":"Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, University of Milan, 20100 Milan, Italy"},{"name":"Fondazione IRCCS C\u00e0 Granda, Ospedale Maggiore Policlinico, 20100 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alberto","family":"Caprioglio","sequence":"additional","affiliation":[{"name":"Department of Biomedical, Surgical and Dental Sciences, School of Dentistry, University of Milan, 20100 Milan, Italy"},{"name":"Fondazione IRCCS C\u00e0 Granda, Ospedale Maggiore Policlinico, 20100 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"890","DOI":"10.1016\/j.dental.2005.03.007","article-title":"Comparative assessment of the roughness, hardness, and wear resistance of aesthetic bracket materials","volume":"21","author":"Zinelis","year":"2005","journal-title":"Dent. 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