{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T05:05:29Z","timestamp":1789707929838,"version":"4.0.1"},"reference-count":20,"publisher":"Frontiers Media SA","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":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Dent. Med."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Thermoforming of clear aligners causes non-uniform material thinning that may influence the structural and mechanical characteristics of the aligners. While greater model base height (MBH) has been shown to increase thinning in single-layer aligners, its effect on dual-layer materials remains unclear. This study aimed to evaluate the effect of four MBH levels (2, 4, 6, and 8 mm) on the thickness distribution of thermoformed Zendura FLX dual-layer clear aligners.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Forty Zendura FLX aligners were thermoformed over standardized 3D-printed maxillary models with MBH of 2, 4, 6, and 8 mm (\n                      <jats:italic>n<\/jats:italic>\n                      \u2009=\u200910 per group). Thickness was measured at multiple tooth-specific sites across four representative teeth (central incisor, canine, first premolar, and first molar) using a digital caliper. Linear mixed-effects models and generalized linear mixed-effects models with a gamma distribution were used for statistical analysis. Estimated marginal means (EMMs) and 95% confidence intervals (CIs) were derived from the fitted models to summarize group-level thickness estimates.\n                      <jats:italic>Post-hoc<\/jats:italic>\n                      pairwise comparisons were performed using Tukey's test, with significance set at\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&amp;lt;\u20090.05.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      EMM thickness decreased progressively with increasing MBH: 446 \u00b5m (95% CI 432\u2013460) at MBH 2 mm, 386 \u00b5m (95% CI 374\u2013399) at MBH 4 mm, 329 \u00b5m (95% CI 319\u2013340) at MBH 6 mm, and 268 \u00b5m (95% CI 260\u2013277) at MBH 8 mm (all pairwise comparisons\n                      <jats:italic>p<\/jats:italic>\n                      \u2009&amp;lt;\u20090.001). This decreasing trend was consistent across all tooth types and measurement sites, though the magnitude of reduction varied by site. Palatal sites consistently exhibited greater thickness than facial sites. For most tooth type\u2013site combinations, all MBH contrasts were statistically significant, with limited exceptions observed at specific sites for anterior teeth, molars, and premolars.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Increasing MBH resulted in a progressive reduction in the thickness of thermoformed Zendura FLX dual-layer clear aligners across all tooth types and measurement sites. Among the four levels tested, an MBH of approximately 4 mm appeared to provide a more balanced thickness distribution. These findings suggest that MBH should be considered as an important fabrication parameter in clear aligner production.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fdmed.2026.1889969","type":"journal-article","created":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T04:33:57Z","timestamp":1789706037000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Effect of 3D-printed model base height on thickness distribution of thermoformed zendura FLX dual-layer clear aligners: an in vitro study"],"prefix":"10.3389","volume":"7","author":[{"given":"Thi-Bich-Van","family":"Tran","sequence":"first","affiliation":[{"name":"Faculty of Dentistry, University of Medicine and Pharmacy at Ho Chi Minh City","place":["Vietnam"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ngoc-Anh-Thu","family":"Pham","sequence":"additional","affiliation":[{"name":"Faculty of Dentistry, University of Medicine and 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of thermoforming on the mechanical, optical, chemical, and morphological properties of PET-G: in vitro study","volume":"16","author":"Staderini","year":"2024","journal-title":"Polymers (Basel)"},{"key":"B11","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1111\/ocr.70067","article-title":"Mechanical properties of thermoplastic materials for clear orthodontic aligners: a new three-dimensional experimental setting","volume":"29","author":"Pozzan","year":"2026","journal-title":"Orthod Craniofac Res"},{"key":"B12","doi-asserted-by":"publisher","first-page":"694","DOI":"10.1016\/j.ajodo.2019.05.012","article-title":"Mechanical and geometric properties of thermoformed and 3D printed clear dental aligners","volume":"156","author":"Jindal","year":"2019","journal-title":"Am J Orthod Dentofacial Orthop"},{"key":"B13","year":""},{"key":"B14","doi-asserted-by":"publisher","first-page":"258","DOI":"10.1007\/s00784-024-05662-x","article-title":"Effect of material composition and thickness 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