Comparative mechanical performance of thermoplastic materials for clear aligners under simulated oral conditions.

IF 2.3 3区医学 Q1 DENTISTRY, ORAL SURGERY & MEDICINE

Korean Journal of Orthodontics Pub Date : 2025-09-25 Epub Date: 2025-06-16 DOI:10.4041/kjod25.094

Miao Liu, Yajie Wang, Ce Bian, Yang Han, Xuan Qin, Jingyao Sun, Yuxing Bai, Ning Zhang

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引用次数: 0

Abstract

Objective: To assess the suitability of polycyclohexylenedimethylene terephthalate glycol (PCTG) for orthodontic aligners and to compare the mechanical properties and 14-day stress relaxation behavior of different materials under simulated oral conditions, offering clinical guidance for material selection.

Methods: Materials used were Maxflex, Scheu, and Fusion Align, consisting of thermoplastic polyurethane (TPU), polyethylene terephthalate glycol (PETG), and PCTG, respectively. The following experiments were conducted: (1) tensile testing at 23°C and under simulated oral conditions; (2) prediction of 14-day stress relaxation using the time-temperature superposition principle; (3) right-angle tear strength testing; and (4) Shore D hardness testing.

Results: Mechanical properties followed the trend TPU > PETG > PCTG in elastic modulus, yield strength, right-angle tear strength, and Shore D hardness (P < 0.05); PETG > PCTG > TPU in yield strain (P < 0.05). TPU showed higher elongation at break than PETG and PCTG (P < 0.05), with no significant difference between PETG and PCTG (P > 0.05). Stress relaxation behavior was predicted based on the time-temperature superposition principle. With prolonged duration, the stress ranking progressively shifted from TPU > PETG > PCTG to PCTG > PETG > TPU.

Conclusions: PCTG exhibits light and sustained force, but its tear resistance and hardness are relatively low. In contrast, TPU demonstrates excellent tear resistance and hardness but experiences rapid force decay.

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在模拟口腔条件下用于清洁矫正器的热塑性材料的力学性能比较。

目的：评价聚环己二甲基对苯二甲酸乙二醇酯（PCTG）作为正畸矫正器的适用性，比较不同材料在模拟口腔条件下的力学性能和14天应力松弛行为，为临床选择材料提供指导。方法：使用的材料为Maxflex、Scheu和Fusion Align，分别由热塑性聚氨酯（TPU）、聚对苯二甲酸乙二醇酯（PETG）和PCTG组成。进行了以下实验：(1)在23℃和模拟口腔条件下的拉伸试验；(2)利用时间-温度叠加原理预测14天应力松弛；(3)直角撕裂强度试验；(4)邵氏D硬度试验。结果：TPU > PETG > PCTG的力学性能在弹性模量、屈服强度、直角撕裂强度、邵氏D硬度等方面均符合趋势（P < 0.05）；PETG > PCTG > TPU屈服应变（P < 0.05）。TPU的断裂伸长率高于PETG和PCTG (P < 0.05)，而PETG和PCTG之间差异无统计学意义（P < 0.05）。基于时间-温度叠加原理预测了应力松弛行为。随着时间的延长，应力排序由TPU > PETG > PCTG逐渐向PCTG > PETG > TPU转变。结论：PCTG重量轻，受力持久，但抗撕裂性和硬度较低。相比之下，TPU具有优异的抗撕裂性和硬度，但经历了快速的力衰减。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Korean Journal of Orthodontics DENTISTRY, ORAL SURGERY & MEDICINE-

CiteScore

3.50

自引率

10.50%

发文量

审稿时长

>12 weeks

期刊介绍： The Korean Journal of Orthodontics (KJO) is an international, open access, peer reviewed journal published in January, March, May, July, September, and November each year. It was first launched in 1970 and, as the official scientific publication of Korean Association of Orthodontists, KJO aims to publish high quality clinical and scientific original research papers in all areas related to orthodontics and dentofacial orthopedics. Specifically, its interest focuses on evidence-based investigations of contemporary diagnostic procedures and treatment techniques, expanding to significant clinical reports of diverse treatment approaches. The scope of KJO covers all areas of orthodontics and dentofacial orthopedics including successful diagnostic procedures and treatment planning, growth and development of the face and its clinical implications, appliance designs, biomechanics, TMJ disorders and adult treatment. Specifically, its latest interest focuses on skeletal anchorage devices, orthodontic appliance and biomaterials, 3 dimensional imaging techniques utilized for dentofacial diagnosis and treatment planning, and orthognathic surgery to correct skeletal disharmony in association of orthodontic treatment.