Based on the role of properties of aligner materials on their efficiency, we aimed to assess their thermomechanical properties after thermoforming and simulated aging. 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. 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. Thermoforming had more prominent role than aging in diminishing of thermomechanical properties. In general, Duran had greater thermomechanical stability than Erkodur.

中文翻译：

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热成型和老化后透明矫正器的动态机械和热性能

基于矫正器材料的特性对其效率的作用，我们旨在评估它们在热成型和模拟老化后的热机械特性。在该实验研究中，制备了 96 个聚对苯二甲酸乙二醇酯 (PETG) 矫正器样品（Duran 和 Erkodur）并将其分为三组：对照（C）、热成型后（T）、热成型和老化后（TA）。通过 3D 打印模具进行热成型，在 37°C 蒸馏水中浸泡 24 小时后，通过 200 次热循环进行老化。对弯曲模量、硬度、玻璃化转变温度 (Tg)、弹性和粘性模量以及损耗因子进行了评估。进行了双向 ANOVA、T 独立和 Tukey HSD 检验以进行统计分析，显着性水平设为 0.05。在这两种材料中，弯曲模量在热成型后显着降低，在 Duran 中为 88%，在 Erkodur 中为 70%，但在老化后没有显着变化。热成型后，两种材料的硬度均显着降低（Duran 为 22%，Erkodur 为 7.6%）。两种材料的 T 和 TA 的动态 Tg 显着降低。在 Duran 的所有温度（25、37、55°C）下，弹性模量差异仅在 C 和 TA 之间显着，但在 Erkodur 中，T 显着降低，老化后没有显着变化。粘性模量和损耗因子在所有温度下都显示出相同的变化模式。在这两种材料中，它们在热成型后增加，但在老化后没有显着变化。热成型在降低热机械性能方面比老化具有更突出的作用。一般来说，