Influence of different 3D printed model's base height on thermoformed aligner thickness

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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
1 Department of Orthodontics, University of Split School of Medicine
2 Department of Endodontics and Restorative Dental Medicine, University of Split School of Medicine
3 Department of Maxillofacial Surgery, University Hospital of Split
*danijela.kalibovic.govorko@mefst.hr, ORCID 0000-0002-2598-9009
Influence of different 3D printed model's base height on thermoformed
aligner thickness
Aim
Reducing the base of the 3D- printed model can significantly reduce the consumption of printing
resin and the environmental impact. However, it is necessary to determine whether the height of
the base affects the thickness of the thermoformed aligner which subsequently affects their
mechanical properties.
Materials and Methods
Thermoformed aligners were produced on four different 3D printed models with different clinical
situations: normal arch, crowding in both arches, protrusion in upper arch and crowding in lower
arch, and protrusion in upper arch with normal lower arch. Each of them was printed with two
different base heights, 2mm and 12mm from the lowest gingival margin respectively. Transparent
0.75 mm thick PET-G foil (Duran+, SCHEU-DENTAL GmbH, Iserlohn, Germany) was used for
thermoforming on Biostar® device (Biostar®, SCHEU-DENTAL GmbH, Iserlohn, Germany).
Three independent measurers measured the
thickness of the aligners on 40 different points
per aligner, making it 80 points per set (upper
jaw + lower jaw) with electronic micrometer
(ELECTRONIC UNIVERSAL MICROMETER
909.785, Schut Geometrical Metrology,
Groningen, The Netherlands) with accuracy of
0.001mm. GraphPad software (GraphPad
prism 9.13 software, GraphPad Software, San
Diego, California, USA) was used for statistical
analysis.
Results and Conclusions
There was no statistical difference in aligner
thickness between aligners produced on models with different base heights. There was a statistically
significant difference in aligner thickness variability between aligners produced on 3D printed
models of patients with different anomalies, with aligners thermoformed on eugnathic patient’s
model having the most variable thickness.
Our data suggest that the model base height and the intensity of crowding or proclination have no
impact on aligners’ thickness reduction.