Department of Orthodontics, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, Tex.
Department of Orthodontics, School of Dentistry, and Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Tex.
Am J Orthod Dentofacial Orthop. 2020 Dec;158(6):889-897. doi: 10.1016/j.ajodo.2020.03.023.
This study aimed to investigate the effect of print orientation and ultraviolet (UV) light curing duration on the dimensional accuracy of a clear aligner design fabricated directly using 3-dimensional (3D) printing.
A master clear aligner design file was 3D printed on a stereolithography printer using 3 different build angles with respect to the build platform: parallel (Horizontal), perpendicular (Vertical), and 45° (45-Degree) (n = 10/group). The 45° orientation then was used to print aligners for 3 postprint processing treatment groups: 0 minutes of UV light and heat exposure (No Cure); 20 minutes of UV light exposure at 80C (20 Minute), and 40 minutes of UV light exposure at 80C (40 Minute) (n = 10/group). Each part was digitally scanned and superimposed with the input file for 3D deviation analysis. A generalized linear mixed model and post-hoc Tukey contrasts were applied for statistical analysis.
Difficulties were encountered in optical scanning of 3D-printed aligners, resulting in the exclusion of some samples and the No Cure group from the analysis. The average positive and negative deviations were not statistically significantly different among the print orientations, and postprint processing conditions were analyzed and fell within limits of clinical acceptability (0.250 mm). Color deviation maps illustrated localized areas of dimensional deviation that may affect the clinical utility of the printed aligner design.
The print orientation and postprint curing duration have little effect on the overall accuracy of the 3D-printed aligner design under the conditions investigated. However, the potential effects of location-specific deviations on the clinical utility of 3D-printed aligners should be considered in future studies.
本研究旨在探讨打印方向和紫外线（UV）光固化时间对直接使用三维（3D）打印制造的透明矫正器设计的尺寸精度的影响。
使用立体光刻打印机，通过相对于构建平台的 3 个不同构建角度对主透明矫正器设计文件进行 3D 打印：平行（水平）、垂直（垂直）和 45°（45 度）（每组 n=10）。然后，将 45°方向用于打印 3 种后处理处理组的矫正器：不进行 UV 光和热暴露（无固化）；80°C 下曝光 20 分钟的 UV 光（20 分钟）和 80°C 下曝光 40 分钟的 UV 光（40 分钟）（每组 n=10）。对每个部分进行数字扫描，并与输入文件进行叠加，以进行 3D 偏差分析。应用广义线性混合模型和事后 Tukey 对比进行统计分析。
3D 打印矫正器的光学扫描遇到困难，导致一些样本和无固化组被排除在分析之外。打印方向之间的平均正负偏差没有统计学显著差异，并且对后处理条件进行了分析，结果在临床可接受范围内（0.250mm）。颜色偏差图说明了可能影响打印矫正器设计临床实用性的局部尺寸偏差区域。
在研究条件下，打印方向和后处理固化时间对 3D 打印矫正器设计的整体精度影响不大。然而，位置特定偏差对 3D 打印矫正器临床实用性的潜在影响应在未来研究中考虑。
