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Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie

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Open Access 09-12-2021 | Aligner | Original Article

Force decay of polyethylene terephthalate glycol aligner materials during simulation of typical clinical loading/unloading scenarios

Authors: Fayez Elkholy, Silva Schmidt, Falko Schmidt, Masoud Amirkhani, Bernd G. Lapatki

Published in: Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie | Issue 3/2023

Abstract

Background

This in vitro study investigated the effect of three distinct daily loading/unloading cycles on force delivery during orthodontic aligner therapy. The cycles were applied for 7 days and were designed to reflect typical clinical aligner application scenarios.

Materials and methods

Flat polyethylene terephthalate glycol (PET-G) specimens (Duran®, Scheu Dental, Iserlohn, Germany) with thicknesses ranging between 0.4 and 0.75 mm were tested in a three-point-bending testing machine. Measurements comprised loading/unloading intervals of 12 h/12 h, 18 h/6 h, and 23 h/1 h, and specimens were exposed to bidistilled water during loading to simulate intraoral conditions.

Results

A very large decay in force for the PET‑G specimens could already be observed after the first loading period, with significantly different residual force values of 24, 20, and 21% recorded for the 12 h/12 h, 18 h/6 h, and 23 h/1 h loading/unloading modes, respectively (Mann–Whitney U test, p < 0.01). In addition, further decays in force from the first to the last loading period at day 7 of 13.5% (12 h/12 h), 9.7% (18 h/6 h), and 8.4% (23 h/1 h) differed significantly among the three distinct loading modes (Mann–Whitney U test, p < 0.01).

Conclusion

Although the initial material stiffness of PET‑G is relatively high, the transmission of excessive forces is attenuated by the high material-related force decay already within a few hours after intraoral insertion.

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Title: Force decay of polyethylene terephthalate glycol aligner materials during simulation of typical clinical loading/unloading scenarios
Authors: Fayez Elkholy
Silva Schmidt
Falko Schmidt
Masoud Amirkhani
Bernd G. Lapatki
Publication date: 09-12-2021
Publisher: Springer Medizin
Keyword: Aligner
Published in: Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie / Issue 3/2023
Print ISSN: 1434-5293
Electronic ISSN: 1615-6714
DOI: https://doi.org/10.1007/s00056-021-00364-5

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Springer Medicine

Force decay of polyethylene terephthalate glycol aligner materials during simulation of typical clinical loading/unloading scenarios

Abstract

Background

Materials and methods

Results

Conclusion

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Abstract

Background

Materials and methods

Results

Conclusion

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