{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T10:02:21Z","timestamp":1789984941635,"version":"4.0.1"},"reference-count":27,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T00:00:00Z","timestamp":1789689600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Time-dependent force reduction may affect the biomechanical performance of thermoformed clear aligners. This proof-of-concept in vitro study compared initial and 7-day system-level 3D resultant forces of DURAN, ZENDURA FLX, and MESHEET under attachment-free and attachment-integrated conditions. Thirty independently fabricated aligners (n = 5 per condition) were tested on a rigid resin model with FDI tooth 11 positioned at 5\u00b0 of labioversion. Forces were recorded at 1 Hz for 168 h under dry room conditions and summarized at 12 h intervals. Temporal series and group-level normalized decay were evaluated descriptively; no longitudinal inferential analysis was performed. Separate 3 \u00d7 2 two-way ANOVAs assessed absolute resultant force at 0 and 168 h. Higher endpoint forces were observed under the attachment-integrated condition in this experimental setup at 0 h [F(1,24) = 24.510, p &lt; 0.001, partial \u03b72 = 0.505] and 168 h [F(1,24) = 7.175, p = 0.013, partial \u03b72 = 0.230]. However, because testing followed a fixed, nonrandomized sequence, the observed difference cannot be attributed exclusively to attachment condition. Material and interaction effects were not significant at either endpoint. Under the attachment-integrated condition, normalized decay was 51.4%, 48.2%, and 44.5%, while 168 h mean forces were 1.415, 1.664, and 1.558 N, respectively. These findings do not establish decay-rate differences, material superiority, equivalence, or clinical efficacy.<\/jats:p>","DOI":"10.3390\/bioengineering13091081","type":"journal-article","created":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T08:03:47Z","timestamp":1789977827000},"page":"1081","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["In Vitro Comparison of Initial and 7-Day System-Level Resultant Forces in Clear Aligners with Different Layer Structures"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6702-1960","authenticated-orcid":false,"given":"Jeong-Hee","family":"Seo","sequence":"first","affiliation":[{"name":"Research and Development Center, DENTIS Co., Ltd., Daegu 41065, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"validation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"}]},{"given":"Eun-Yeong","family":"Park","sequence":"additional","affiliation":[{"name":"Research and Development Center, DENTIS Co., Ltd., Daegu 41065, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeong-Hyeon","family":"Lee","sequence":"additional","affiliation":[{"name":"National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju 28159, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"software","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8642-9542","authenticated-orcid":false,"given":"Won-Gi","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Dental Technology, Daegu Health College, Daegu 41453, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"resources","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Sung-Jae","family":"Lee","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering, Inje University, Gimhae 50834, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"resources","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7309-5977","authenticated-orcid":false,"given":"Bongju","family":"Kim","sequence":"additional","affiliation":[{"name":"Dental Life Science Research Institute, Seoul National University Dental Hospital, Seoul 03080, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"project-administration","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,18]]},"reference":[{"key":"ref_1","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. 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