Department of Orthodontics, Rutgers School of Dental Medicine, Newark, NJ.
Office of Research, School of Dentistry, University of Texas Health Science Center, Houston, Tex.
Am J Orthod Dentofacial Orthop. 2021 Sep;160(3):451-458.e2. doi: 10.1016/j.ajodo.2020.11.039.
Three-dimensional (3D) printing technologies are profoundly changing the landscape of orthodontics. To optimize treatment-oriented applications, dimensional fidelity is required for 3D-printed orthodontic models. This study aimed to evaluate the effect of build angle and layer height on the accuracy of 3D-printed dental models and if each of their influences on print accuracy was conditional on the other.
A maxillary cast was scanned using an intraoral scanner. One hundred thirty-two study models were printed at various combinations of build angle (0°, 30°, 60°, 90°) and layer height (20 μm, 50 μm, 100 μm) with a digital light processing printer (n = 11 per group). The models were digitally scanned, and deviation analyzed using a 3D best-fit algorithm in metrology software.
A statistically significant interaction was consistently found between build angle and layer height for each positive deviation, negative deviation, and proportion out of bounds. Average deviations of all study models were within clinically acceptable ranges, but the least accurate models were printed at 0°/20 μm. Although there was a tendency for an oblique build angle of 30° or 60° with a smaller layer height of 20 μm or 50 μm to print the most accurate models, 95 % confidence intervals overlapped with all other angles and heights except for 0°/20 μm.
Build angle and layer height have statistically significant interactive effects on the accuracy of 3D-printed dental models. Overall, digital light processing printers produced models within clinically acceptable bounds, but the choice of build angle and layer height should be considered in conjunction with the clinical application, desired print time, and preferred efficiency of each print job.
三维（3D）打印技术正在深刻改变正畸学的面貌。为了优化面向治疗的应用，3D 打印正畸模型需要具有尺寸精度。本研究旨在评估构建角度和层厚对 3D 打印牙模精度的影响，以及它们各自对打印精度的影响是否取决于另一个因素。
使用口腔内扫描仪对上颌模型进行扫描。使用数字光处理打印机以各种构建角度（0°、30°、60°、90°）和层厚（20μm、50μm、100μm）组合打印 132 个研究模型（每组 11 个）。使用计量软件中的 3D 最佳拟合算法对模型进行数字扫描和偏差分析。
对于每个正偏差、负偏差和超出范围的比例，始终在构建角度和层厚之间发现了统计学上显著的相互作用。所有研究模型的平均偏差均在临床可接受范围内，但最不准确的模型是在 0°/20μm 时打印的。尽管有倾向于以较小的层厚（20μm 或 50μm）使用 30°或 60°的斜构建角度打印最准确的模型，但 95%置信区间与除 0°/20μm 以外的所有其他角度和高度重叠。
构建角度和层厚对 3D 打印牙模的精度具有统计学上显著的交互作用。总体而言，数字光处理打印机生产的模型在临床可接受的范围内，但应根据临床应用、所需打印时间和每个打印作业的首选效率综合考虑构建角度和层厚的选择。
