Dynamic mechanical and thermal properties of clear aligners after thermoforming and aging
Abstract Background Based on the role of properties of aligner materials on their efficiency, we aimed to assess their thermomechanical properties after thermoforming and simulated aging. Methods In this experimental study, 96 samples of polyethylene terephthalate glycol (PETG) aligners (Duran and E...
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doaj-915bdf27d7b4479fb951ab03123f26602021-07-04T11:32:32ZengSpringerOpenProgress in Orthodontics2196-10422021-06-0122111110.1186/s40510-021-00362-8Dynamic mechanical and thermal properties of clear aligners after thermoforming and agingKazem Dalaie0Seyyed Mostafa Fatemi1Samin Ghaffari2Department of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical SciencesDepartment of Dental Biomaterials, School of Dentistry, Shahid Beheshti University of Medical SciencesDepartment of Orthodontics, School of Dentistry, Shahid Beheshti University of Medical SciencesAbstract Background Based on the role of properties of aligner materials on their efficiency, we aimed to assess their thermomechanical properties after thermoforming and simulated aging. Methods In this experimental study, 96 samples of polyethylene terephthalate glycol (PETG) aligners (Duran and Erkodur) were prepared and divided to three groups: control (C), after thermoforming (T), after thermoforming and aging (TA). Thermoforming was done through 3D-printed molds, and aging was exerted by 200 thermal cycles after immersion in 37°C distilled water for 24h. Flexural modulus, hardness, glass transition temperature (Tg), elastic and viscous modulus, and loss factor were evaluated. Two-way ANOVA, T-independent, and Tukey HSD tests were done for statistical analysis and significance level was set to 0.05. Results In both materials, flexural modulus decreased significantly after thermoforming, 88% in Duran and 70% in Erkodur, but did not change significantly after aging. After thermoforming, hardness decreased significantly in both materials (22% in Duran and 7.6% in Erkodur). Dynamic Tg was significantly lower in T and TA in both materials. At all temperatures (25, 37, 55°C) in Duran, the elastic modulus difference was only significant between C and TA, but in Erkodur, it decreased significantly in T, and there was no significant change after aging. Viscous modulus and loss factor showed the same change patterns at all temperatures. In both materials, they increased after thermoforming, but did not change significantly after aging. Conclusion Thermoforming had more prominent role than aging in diminishing of thermomechanical properties. In general, Duran had greater thermomechanical stability than Erkodur.https://doi.org/10.1186/s40510-021-00362-8Clear aligner appliancesDentistryDMTAGlass transitionOrthodonticsPolyethylene terephthalate glycol |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Kazem Dalaie Seyyed Mostafa Fatemi Samin Ghaffari |
spellingShingle |
Kazem Dalaie Seyyed Mostafa Fatemi Samin Ghaffari Dynamic mechanical and thermal properties of clear aligners after thermoforming and aging Progress in Orthodontics Clear aligner appliances Dentistry DMTA Glass transition Orthodontics Polyethylene terephthalate glycol |
author_facet |
Kazem Dalaie Seyyed Mostafa Fatemi Samin Ghaffari |
author_sort |
Kazem Dalaie |
title |
Dynamic mechanical and thermal properties of clear aligners after thermoforming and aging |
title_short |
Dynamic mechanical and thermal properties of clear aligners after thermoforming and aging |
title_full |
Dynamic mechanical and thermal properties of clear aligners after thermoforming and aging |
title_fullStr |
Dynamic mechanical and thermal properties of clear aligners after thermoforming and aging |
title_full_unstemmed |
Dynamic mechanical and thermal properties of clear aligners after thermoforming and aging |
title_sort |
dynamic mechanical and thermal properties of clear aligners after thermoforming and aging |
publisher |
SpringerOpen |
series |
Progress in Orthodontics |
issn |
2196-1042 |
publishDate |
2021-06-01 |
description |
Abstract Background Based on the role of properties of aligner materials on their efficiency, we aimed to assess their thermomechanical properties after thermoforming and simulated aging. Methods In this experimental study, 96 samples of polyethylene terephthalate glycol (PETG) aligners (Duran and Erkodur) were prepared and divided to three groups: control (C), after thermoforming (T), after thermoforming and aging (TA). Thermoforming was done through 3D-printed molds, and aging was exerted by 200 thermal cycles after immersion in 37°C distilled water for 24h. Flexural modulus, hardness, glass transition temperature (Tg), elastic and viscous modulus, and loss factor were evaluated. Two-way ANOVA, T-independent, and Tukey HSD tests were done for statistical analysis and significance level was set to 0.05. Results In both materials, flexural modulus decreased significantly after thermoforming, 88% in Duran and 70% in Erkodur, but did not change significantly after aging. After thermoforming, hardness decreased significantly in both materials (22% in Duran and 7.6% in Erkodur). Dynamic Tg was significantly lower in T and TA in both materials. At all temperatures (25, 37, 55°C) in Duran, the elastic modulus difference was only significant between C and TA, but in Erkodur, it decreased significantly in T, and there was no significant change after aging. Viscous modulus and loss factor showed the same change patterns at all temperatures. In both materials, they increased after thermoforming, but did not change significantly after aging. Conclusion Thermoforming had more prominent role than aging in diminishing of thermomechanical properties. In general, Duran had greater thermomechanical stability than Erkodur. |
topic |
Clear aligner appliances Dentistry DMTA Glass transition Orthodontics Polyethylene terephthalate glycol |
url |
https://doi.org/10.1186/s40510-021-00362-8 |
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