Win Pyi Phyo, Lai Szu-Yu, De-Shing Chen Daniel, Sainbayar Bolormaa, Peng Tzu-Yu, Hsin-Chung Cheng Johnson
School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
Division of Orthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan.
J Dent Sci. 2025 Jul;20(3):1723-1730. doi: 10.1016/j.jds.2025.03.034. Epub 2025 Apr 10.
BACKGROUND/PURPOSE: Fixed lingual retainers (FLRs) often experience structural instability, including poor adaptation, and the untwisting of spiral wires, which can lead to unwanted tooth movement. Digital workflows have enhanced the appliance's accuracy. This study evaluated the water sorption (W), water solubility (W), staining resistance, and flexural performance of three-dimensionally printed resin (3DR) to determine its optimal design for FLRs.
Cylindrical 3DR specimens were immersed in distilled water and artificial saliva for 7, 14, and 30 days. W and W were measured according to ISO 4049 guidelines. Color stability was analyzed after 7 days of immersion in staining solutions using the CIEDE2000 formula. Straight 3DR specimens with various cross-sectional shapes and dimensions underwent a three-point bending test, comparing mechanical properties to multistrand stainless-steel wire (MSW). Statistical analysis was performed using a one-way ANOVA with Tukey's post-hoc test ( < 0.05).
W and W values remained within ISO standards, with no significant changes over time. Specimens exposed to red wine, grape juice, and curry exhibited color changes exceeding the acceptability threshold of 1.77, while other solutions caused minimal discoloration. Hemi-elliptical cross-sections demonstrated significantly greater flexural strength than round designs. Although all 3DR specimens fractured before reaching the 2.0-mm deflection limit, some designs exhibited comparable bending strength to MSW while maintaining sufficient flexibility for physiological tooth movement.
A hemi-elliptical 3DR design (1.0 mm thick and 2.0 mm wide) demonstrated stability in the oral environment, moderate stainability, and mechanical performance comparable to MSW, supporting its feasibility for FLRs.
背景/目的：固定舌侧保持器（FLR）常常出现结构不稳定的情况，包括贴合不佳以及螺旋丝解捻，这可能导致不必要的牙齿移动。数字化工作流程提高了矫治器的精度。本研究评估了三维打印树脂（3DR）的吸水性（W）、水溶性（W）、耐染色性和弯曲性能，以确定其用于FLR的最佳设计。
将圆柱形3DR标本浸泡在蒸馏水和人工唾液中7天、14天和30天。根据ISO 4049指南测量W和W。使用CIEDE2000公式分析在染色溶液中浸泡7天后的颜色稳定性。对具有不同横截面形状和尺寸的直3DR标本进行三点弯曲试验，将机械性能与多股不锈钢丝（MSW）进行比较。采用单因素方差分析和Tukey事后检验进行统计分析（<0.05）。
W和W值保持在ISO标准范围内，且随时间无显著变化。暴露于红酒、葡萄汁和咖喱中的标本颜色变化超过了可接受阈值1.77，而其他溶液导致的变色极小。半椭圆形横截面的弯曲强度明显高于圆形设计。尽管所有3DR标本在达到2.0毫米挠度极限之前就发生了断裂，但一些设计在保持足够的生理牙齿移动灵活性的同时，表现出与MSW相当的弯曲强度。
半椭圆形3DR设计（厚1.0毫米，宽2.0毫米）在口腔环境中表现出稳定性、适度的可染色性以及与MSW相当的机械性能，支持其用于FLR的可行性。
