目的 本研究旨在评估由锥形束计算机断层扫描 (CBCT) 转换数据的数字模型制成的 3D 打印临时牙冠的边缘和内部间隙。材料和方法 从用于单冠修复的患者身上获取 16 个聚乙烯硅氧烷印模,并使用 CBCT 进行扫描。使用定制开发的软件将扫描数据转换为正标准三角测量语言 (STL) 文件。使用口内光学扫描仪 (IOS) 扫描制作的石材模型,以将表面精度与 CBCT 获得的 STL 数据进行比较。转换后的 STL 文件用于使用数字光处理 3D 打印机用光聚合物制造临时牙冠。采用复制法来分析准确性。用数码显微镜测量每个临时牙冠复制品样本的边缘和内部间隙。进行 Friedman 检验和 Mann-Whitney U 检验(Wilcoxon 符号秩检验),以 95% 的置信水平比较边缘和内部差距的测量结果。结果 CBCT和IOS的均方根值范围为41.00~126.60 μm,平均值为60.12 μm。边缘间隙、内部间隙和总间隙的平均值分别为 132.96 (±139.23) μm、137.86 (±103.09) μm 和 135.68 (±120.30) μm。近远中和颊舌面的边缘或内部间隙没有统计学上的显着差异,但边缘面积(132.96μm)和咬合面积(255.88μm)具有显着的平均差异。结论 基于 CBCT STL 数据制作的临时牙冠的边缘间隙在临床成功的可接受范围内。 通过高分辨率 CBCT 和数字模型转换技术的不断发展,CBCT 可能成为获取临时牙冠制造数字模型的替代方法。
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Accuracy evaluation of 3D printed interim prosthesis fabrication using a CBCT scanning based digital model.
OBJECTIVES
This study aimed to evaluate the marginal and internal gaps in 3D-printed interim crowns made from digital models of cone-beam computed tomography (CBCT) conversion data.
MATERIALS AND METHODS
Sixteen polyvinylsiloxane impressions were taken from patients for single crown restorations and were scanned using CBCT. The scanning data were converted to positive Standard Triangulation Language (STL) files using custom-developed software. The fabricated stone models were scanned with an intraoral optical scanner (IOS) to compare the surface accuracy with the STL data obtained by CBCT. The converted STL files were utilized to fabricate interim crowns with a photopolymer using a digital light-processing 3D printer. The replica method was used to analyze the accuracy. The marginal and internal gaps in the replica specimen of each interim crown were measured with a digital microscope. The Friedman test and Mann-Whitney U test (Wilcoxon-signed rank test) were conducted to compare the measurements of the marginal and internal gaps with a 95% level of confidence.
RESULTS
The root-mean-square values of the CBCT and IOS ranged from 41.00 to 126.60 μm, and the mean was 60.12 μm. The mean values of the marginal, internal, and total gaps were 132.96 (±139.23) μm, 137.86 (±103.09) μm, and 135.68 (±120.30) μm, respectively. There were no statistically significant differences in the marginal or internal gaps between the mesiodistal and buccolingual surfaces, but the marginal area (132.96 μm) and occlusal area (255.88 μm) had significant mean differences.
CONCLUSION
The marginal gap of the fabricated interim crowns based on CBCT STL data was within the acceptable range of clinical success. Through ongoing developments of high-resolution CBCT and the digital model conversion technique, CBCT might be an alternative method to acquire digital models for interim crown fabrication.