Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Korea.
Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, Seoul, 03722, Korea.
Prog Orthod. 2022 Nov 21;23(1):39. doi: 10.1186/s40510-022-00436-1.
With advances in digital technology, new types of lingual fixed retainers are being developed. However, there are few studies that quantitatively evaluate the accuracy and stability of lingual fixed retainers. The aim of this study was to assess the accuracy and stability of two types of computer-aided customized lingual fixed retainers and a conventional lingual fixed retainer.
A total of 10 maxillary and 10 mandibular duplicated dental models were selected, and then, three types of retainers were fabricated on the canine-to-canine area for each model. To evaluate accuracy, wire clearance at interproximal area (WCI) was measured using superimposition analysis. Initial flatness deformation was also measured for vertical distortion of retainers. Lateral width, anteroposterior length, and flatness deformation were measured at three-time points for stability assessment. Thermocycling was used to induce 6 months of time flow.
The custom-bent group showed significantly higher WCI than the custom-cut and manual groups in the maxillary arch (P = 0.002). The custom-cut group showed significantly less flatness deformation, which was followed by the custom-bent and manual groups in both the maxillary and mandibular arch (P < 0.001). There was no significant difference in stability between the three retainer groups during 5100 cycles of thermocycling (corresponding to 6-month period).
Since there was no difference in stability between the three groups, it is recommended to use custom-cut type retainers in light of accuracy. However, accuracy and stability are not the only factors to consider when selecting type of retainers. Because each retainer has advantages and disadvantages, the type of retainers should be decided in consideration of the clinical environment.
随着数字技术的进步，新型的舌侧固定保持器正在被开发。然而，目前很少有研究对舌侧固定保持器的准确性和稳定性进行定量评估。本研究旨在评估两种计算机辅助定制舌侧固定保持器和一种传统舌侧固定保持器的准确性和稳定性。
共选择了 10 个上颌和 10 个下颌的复制牙模，然后在上颌和下颌的尖牙到尖牙区域为每个模型制作三种保持器。为了评估准确性，使用叠加分析测量近中区域的导丝间隙（WCI）。初始平整度变形也用于测量保持器的垂直变形。稳定性评估时在三个时间点测量侧向宽度、前后长度和平整度变形。热循环用于模拟 6 个月的时间流逝。
在上颌弓中，定制弯曲组的 WCI 显著高于定制切割组和手动组（P = 0.002）。定制切割组的平整度变形显著较小，其次是定制弯曲组和手动组在上颌和下颌弓中（P < 0.001）。在 5100 次热循环（相当于 6 个月的时间）期间，三种保持器组之间的稳定性没有差异。
鉴于三组之间的稳定性没有差异，建议根据准确性使用定制切割型保持器。然而，准确性和稳定性不是选择保持器类型时唯一需要考虑的因素。由于每种保持器都有优点和缺点，因此应根据临床环境考虑选择哪种保持器。
