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The influence of material properties on thermoformed aligner thickness
Ružica Bandić 1†, Katarina Vodanović 1†, Ivna Vuković Kekez 1, Ivana Medvedec Mikić 2,3, Danijela Kalibović Govorko 1,2*
†authors contributed equally to this work
1Department of Orthodontics, University of Split School of Medicine
2Department of Endodontics and Restorative Dental Medicine, University of Split School of Medicine
3Department of Maxillofacial Surgery, University Hospital of Split
*danijela.kalibovic.govorko@mefst.hr, ORCID 0000-0002-2598-9009
The aim of this study was to assess the reduction of thermoformed aligners’ thickness made of different materials.
Aligners were thermoformed using Biostar® device (Biostar®, SCHEU-DENTAL GmbH, Iserlohn, Germany) on four 3D-printed models with
different clinical situations. Single-layered materials: Duran+ (0.5, 0.625, 0.75; PET-G; Duran+, SCHEU-DENTAL GmbH); Erkodur (0.5, 0.6, 0.8;
PET-G; Erkodur, Erkodent Erich Kopp GmbH, Pfalzgrafenweiler, Germany); Zendura A (0.76; TPU; Zendura A, Bay Materials LLC, Fremont,
California, USA). Multi-layered materials: Erkoloc-Pro (1.0, 1.3; PET-G+TPU; Erkoloc-Pro, Erkodent Erich Kopp GmbH); Zendura FLX (0.76;
TPU+elastomer; Zendura FLX, Bay Materials LLC); CA PRO+ (0.75; copolyester+TPU; CA PRO+, SCHEU-DENTAL GmbH). Measurements were
done by three independent measurers using electronic micrometer (ELECTRONIC UNIVERSAL MICROMETER, Schut Geometrical Metrology,
Groningen, The Netherlands, accuracy: 0.001mm). GraphPad software (GraphPad prism 9.13 software, GraphPad Software, San Diego,
California, USA) was used for statistical analysis.
The greatest relative thickness thinning of material showed Erkoloc-Pro 1.0 mm (78%), while the least relative thinning showed Zendura A
0.76 (66%). The greatest thickness variability showed Erkodur 0.5 (from 0.465 to 0.13) and Zendura A 0.76 (from 0.762 to 0.258). The greatest
thickness variability showed mesio-buccal cusp of lower right first molar (Zendura A 0.76). All of the materials have at least one measured
point in the group of 3% most variable points, with the exception of Zendura A 0.76, in the group of 3% least variable points.
When choosing a suitable aligner material, its properties should be carefully considered. The thickness thinning might affect aligners’
mechanical properties and subsequent tooth movement.
This research was co-financed by the European Union from the European Regional Development Fund under the Operational Program
Competitiveness and Cohesion 2014-2020