Angle Orthod. 2021 Jan 1;91(1):98-104. doi: 10.2319/040420-254.1.
The need for intraoral scanning in the presence of brackets has increased for monitoring tooth movement during orthodontic treatment. The purpose of this study was to evaluate the effect of orthodontic brackets bonded to tooth surfaces on intraoral scans.
Intraoral scans were performed in 30 patients using both iTero and Trios scanners before and after bonding of the brackets. The two sets of intraoral scans of each patient and intraoral scans with and without brackets were superimposed using a best-fit algorithm, and three-dimensional (3D) surface analysis was performed. In each superimposition, discrepancies in the 3D axes and arch-width measurements in the incisor and molar regions were compared. In addition, the range of distortion around the brackets was evaluated on the cross sections of each superimposition.
The overall discrepancies between the intraoral scans with and without brackets were within 0.30 mm. The arch-width discrepancies in the molar region were greater than those in the incisor region, but the differences were not statistically significant (P = .972 for iTero; P = .960 for Trios). The cross sections of the superimposed intraoral scans with and without brackets showed that the deviations were within 0.40 mm in the horizontal section and within 0.35 mm in the vertical section around the brackets.
The results of this study indicate that the accuracy of intraoral scans, even in the presence of brackets, is clinically acceptable, and the regions beyond 0.50 mm around the brackets should be used for superimposition on images without brackets.
在正畸治疗中监测牙齿移动时,需要在有托槽的情况下进行口内扫描。本研究的目的是评估粘结于牙面的正畸托槽对口腔内扫描的影响。
30 名患者分别使用 iTero 和 Trios 扫描仪在粘结托槽前后进行口内扫描。将每位患者的两组口内扫描以及有托槽和无托槽的口内扫描使用最佳拟合算法进行叠加,并进行三维(3D)表面分析。在每次叠加中,比较 3D 轴和切牙及磨牙区域弓宽测量的差异。此外,还评估了每个叠加的横截面中托槽周围的扭曲范围。
有托槽和无托槽的口内扫描之间的总体差异在 0.30mm 以内。磨牙区域的弓宽差异大于切牙区域,但差异无统计学意义(iTero 为 P =.972;Trios 为 P =.960)。叠加的口内扫描的横截面显示,在水平截面中偏差在 0.40mm 以内,在垂直截面中偏差在托槽周围 0.35mm 以内。
本研究结果表明,即使存在托槽,口内扫描的准确性在临床也是可接受的,应在距托槽 0.50mm 以外的区域进行无托槽图像的叠加。