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Introduction Retention is essential to prevent unwanted tooth movement due to growth changes, to allow the gingival and periodontal tissues affected by orthodontic treatment to realign, and to stabilize teeth that have been moved to potentially unstable positions, thus reducing the risk of relapse. This study aimed to evaluate the distortion of Essix retainers over time to enhance their retention and stability. Methods Patients who visited the Department of Orthodontics and Dentofacial Orthopedics at Ranjeet Deshmukh Dental College & Research Centre, Nagpur, India, after completing their orthodontic treatment were included in the study, according to the established inclusion and exclusion criteria. A total of 26 patients participated. Each patient received an Essix retainer fabricated from a Duran+ Biostar round sheet (1 mm thickness) using a Biostar machine based on their post-debonded maxillary cast. The patients were instructed on the correct insertion and removal of the Essix retainer. The inner surface of the retainers was scanned at one month, three months, and six months using an intraoral digital scanner. These scans were analyzed and compared for distortion at different time intervals using Medit software. Results The Essix retainers exhibited varying degrees of distortion at different time intervals. Notably, distortion was more significant in the posterior region compared to the anterior region. Additionally, distortion increased over time, with the least amount observed at one month and progressively worsening by the sixth month. Specifically, the average distortion in the posterior region ranged from 0.133 mm after the first month to 0.304 mm after six months. In contrast, the average distortion in the anterior region was lower, ranging from 0.057 mm at one month to 0.068 mm at six months. Conclusions Distortion was more pronounced on the posterior surface of the Essix retainer compared to the anterior region.

引言

保持对于防止因生长变化导致的不必要牙齿移动至关重要，它能使受正畸治疗影响的牙龈和牙周组织重新排列，并稳定已移动到潜在不稳定位置的牙齿，从而降低复发风险。本研究旨在评估埃西克斯保持器随时间的变形情况，以增强其保持力和稳定性。

方法

根据既定的纳入和排除标准，纳入在印度那格浦尔兰吉特·德什穆克牙科学院及研究中心正畸与牙颌面正畸科完成正畸治疗后前来就诊的患者。共有26名患者参与。根据每位患者脱粘结后的上颌模型，使用Biostar机器用Duran + Biostar圆形薄片（厚度1毫米）制作埃西克斯保持器。指导患者正确佩戴和取下埃西克斯保持器。使用口腔内数字扫描仪在1个月、3个月和6个月时对保持器的内表面进行扫描。使用Medit软件对这些扫描结果进行分析，并比较不同时间间隔的变形情况。

结果

埃西克斯保持器在不同时间间隔呈现出不同程度的变形。值得注意的是，与前部区域相比，后部区域的变形更为明显。此外，变形随时间增加，1个月时观察到的变形量最少，到第6个月逐渐恶化。具体而言，后部区域的平均变形从第1个月后的0.133毫米增加到6个月后的0.304毫米。相比之下，前部区域的平均变形较低，从1个月时的0.057毫米到6个月时的0.068毫米。

结论

与前部区域相比，埃西克斯保持器后表面的变形更为明显。