{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T06:57:56Z","timestamp":1790578676715,"version":"4.1.0"},"reference-count":23,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T00:00:00Z","timestamp":1790035200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T00:00:00Z","timestamp":1790553600000},"content-version":"vor","delay-in-days":6,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["BMC Oral Health"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Maxillary molar mesialization with clear aligners is challenging because achieving controlled root movement without excessive mesial tipping remains difficult. Although power arms can modify the force system, the combined effects of power-arm length and attachment configuration on molar displacement and tipping remain insufficiently characterized. This study evaluated the effects of 6-, 8-, and 10-mm power arms combined with two attachment configurations during maxillary first molar mesialization using three-dimensional finite element analysis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>The attachment configurations were selected to represent two clinically distinct approaches to integrating a vertical attachment with a power arm: a palatal vertical attachment combined with a buccal cut-out and a buccal vertical attachment with direct power-arm integration. Six three-dimensional finite element models were constructed by combining three power arm lengths (6, 8, and 10\u00a0mm) with two attachment configurations: a palatal vertical attachment with a buccal cut-out, and a buccal vertical attachment without a cut-out. A mesial force of 200\u00a0g was applied from a temporary anchorage device (TAD) to the power arm. Displacements were measured along the X (bucco\u2013palatal), Y (mesio\u2013distal), and Z (occluso\u2013gingival) axes. Peak von Mises stress values in the periodontal ligament and aligner deformation were evaluated.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>In all models, maxillary first molar displacement occurred predominantly in the mesial and gingival directions. Mesial crown displacement ranged from 0.068 to 0.074\u00a0mm, while distal displacement at the root apex ranged from 0.011 to 0.012\u00a0mm. Mesial tipping angles ranged from 0.155\u00b0 to 0.170\u00b0, with higher tipping observed in models with shorter power arms. Increasing power arm length was consistently associated with reduced mesial tipping and lower periodontal ligament stress, but with reduced mesial crown displacement. Shorter power arms generated higher periodontal ligament stress, whereas longer power arms were associated with greater aligner deformation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Power arm length and attachment configuration were associated with differences in initial tooth displacement patterns, periodontal ligament stress distribution, and aligner deformation during maxillary first molar mesialization with clear aligners. Longer power arms were associated with reduced mesial tipping and lower periodontal ligament stress, but also with reduced mesial crown displacement. The buccal vertical attachment configuration consistently produced lower mesial rotation than the palatal vertical attachment with buccal cut-out configuration at each corresponding power-arm length; this difference should be interpreted as a configuration-dependent finding within the initial biomechanical response.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12903-026-09893-0","type":"journal-article","created":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T03:55:35Z","timestamp":1790049335000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effect of power arm length and attachment configuration on maxillary molar mesialization with clear aligners: a finite element analysis"],"prefix":"10.1186","volume":"26","author":[{"given":"Ahmet","family":"Cavusoglu","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Buket","family":"Erdem","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,9,22]]},"reference":[{"key":"9893_CR1","doi-asserted-by":"publisher","first-page":"127","DOI":"10.1111\/ocr.12177","volume":"20","author":"M Zheng","year":"2017","unstructured":"Zheng M, Liu R, Ni Z, Yu Z. Efficiency, effectiveness and treatment stability of clear aligners: a systematic review and meta-analysis. Orthod Craniofac Res. 2017;20:127\u201333. https:\/\/doi.org\/10.1111\/ocr.12177.","journal-title":"Orthod Craniofac Res"},{"key":"9893_CR2","doi-asserted-by":"publisher","first-page":"1011","DOI":"10.2147\/PPA.S257814","volume":"14","author":"RA Alansari","year":"2020","unstructured":"Alansari RA. Youth perception of different orthodontic appliances. Patient Prefer Adherence. 2020;14:1011\u20139. https:\/\/doi.org\/10.2147\/PPA.S257814.","journal-title":"Patient Prefer Adherence"},{"key":"9893_CR3","doi-asserted-by":"publisher","first-page":"251","DOI":"10.1177\/14653125241229456","volume":"51","author":"J Paim","year":"2024","unstructured":"Paim J, de Souza LFD, Fialho T, et al. Assessment of patients\u2019 knowledge and preferences for the use of orthodontic aligners. 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All procedures were performed in accordance with the ethical standards of the institutional research committee and with the 1964 Declaration of Helsinki and its later amendments. The study did not involve human participants, human tissue, or identifiable patient data. The anatomical geometry used for finite element model construction was derived from the publicly available Visible Human Project dataset (National Library of Medicine, Bethesda, MD, USA); consent to participate was therefore not applicable.","order":1,"name":"Ethics","label":"Ethics approval and consent to participate","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"Not applicable. This manuscript does not contain any individual person\u2019s identifiable data, images or videos.","order":2,"name":"Ethics","label":"Consent for publication","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":3,"name":"Ethics","label":"Competing interests","group":{"name":"EthicsHeading","label":"Declarations"}}],"article-number":"1854"}}