Department of Prosthodontics, Bahçeşehir University School of Dental Medicine, Istanbul, Turkey.
Department of Restorative Dentistry, University of Illinois at Chicago College of Dentistry, Chicago, IL.
J Prosthodont. 2021 Feb;30(2):163-170. doi: 10.1111/jopr.13264. Epub 2020 Sep 26.
The accuracy of digital impressions is still controversial for complete arch implant cases. The aim of this study is to compare the accuracy of different intraoral scanners with the conventional technique in terms of trueness and precision in a complete arch implant model.
Eight implants were inserted asymmetrically in a polyurethane edentulous mandibular model with different angulations. A 3-dimensional (3D) reference model was obtained by scanning this polyurethane model with an optical scanner. First, digital impressions were made by using 3 different intraoral scanners: Carestream 3500 (DC), Cerec Omnicam (DO) and 3Shape Trios 3 (DT). Subsequently, a nonsplinted open tray impression technique was used for conventional impression group (C) and then the master casts were digitalized with a lab scanner. Each 10 STL files belonging to 4 different impression groups were imported to a reverse engineering program, to measure distance and angle deviations from the reference model. All statistical analyses were performed after taking absolute values of the data. After comparing the impression groups with one-way ANOVA, the trueness and precision values were analyzed by Tukey post hoc test and 0.05 was used as the level of significance.
The mean trueness of distance was 123.06 ± 89.83 µm for DC, 229.72 ± 121.34 µm for DO, 209.75 ± 47.07 µm for DT, and 345.32 ± 75.12 µm for C group (p < 0.0001). While DC showed significantly lower deviation compared to DO and C, no significant difference was found between DC and DT. C showed the highest distance deviation significantly in all groups; and no significant difference was found between DO and DT groups. In angle measurements; the trueness was 0.26° ± 0.07° for DC, 0.53° ± 0.42° for DO, 0.33° ± 0.30° for DT, and 0.74° ± 0.65° for C group. There was no significant difference between the groups in terms of angular trueness (p = 0.074). In terms of the precision for distance, the results of DC 80.43 ± 29.69 µm, DO 94.06 ± 69.96 µm, DT 35.55 ± 28.46 µm and C 66.97 ± 36.69 µm were determined (p = 0.036). The significant difference was found only between DT and DO among all groups. Finally, angular precision was determined to be 0.19° ± 0.11° for DC, 0.30° ± 0.28° for DO, 0.22° ± 0.19° for DT, and 0.50° ± 0.38° for Group C. No significant difference was found between the groups, in terms of angular precision (p = 0.053).
All digital impression groups yielded superior data compared to conventional technique in terms of trueness. DC formed the impression group with the highest trueness in both distance and angular measurements. The results of this in vitro study suggest the use of intraoral scanners compared to the conventional impression techniques in complete arch implant cases with high angulations.
数字化印模的准确性对于全颌种植病例仍然存在争议。本研究旨在比较不同的口内扫描仪与传统技术在全颌种植模型中准确性的差异，包括准确性和精密度。
将 8 个种植体以不同的角度不对称地植入一个聚氨酯无牙下颌模型中。通过使用光学扫描仪扫描这个聚氨酯模型，获得了一个三维（3D）参考模型。首先，使用 3 种不同的口内扫描仪（Carestream 3500 [DC]、Cerec Omnicam [DO]和 3Shape Trios 3 [DT]）进行数字化印模。随后，使用无支架开口托盘印模技术对常规印模组（C 组）进行印模，然后使用实验室扫描仪对石膏模型进行数字化。将每组 10 个 STL 文件导入到逆向工程程序中，以测量与参考模型的距离和角度偏差。对所有数据进行绝对值比较后，进行单因素方差分析。在比较各组后，采用 Tukey 事后检验分析准确性和精密度值，以 0.05 为显著性水平。
DC 组的距离准确性为 123.06 ± 89.83 µm，DO 组为 229.72 ± 121.34 µm，DT 组为 209.75 ± 47.07 µm，C 组为 345.32 ± 75.12 µm（p < 0.0001）。与 DO 和 C 组相比，DC 组的偏差明显较低，而 DC 组和 DT 组之间无显著差异。C 组在所有组中表现出最高的距离偏差，且与 DO 和 DT 组之间无显著差异。在角度测量方面，DC 组的准确性为 0.26° ± 0.07°，DO 组为 0.53° ± 0.42°，DT 组为 0.33° ± 0.30°，C 组为 0.74° ± 0.65°。各组之间的角度准确性无显著差异（p = 0.074）。在距离精密度方面，DC 组的结果为 80.43 ± 29.69 µm，DO 组为 94.06 ± 69.96 µm，DT 组为 35.55 ± 28.46 µm，C 组为 66.97 ± 36.69 µm（p = 0.036）。在所有组中，仅在 DT 组和 DO 组之间发现显著差异。最后，DC 组的角度精密度为 0.19° ± 0.11°，DO 组为 0.30° ± 0.28°，DT 组为 0.22° ± 0.19°，C 组为 0.50° ± 0.38°。各组之间的角度精密度无显著差异（p = 0.053）。
与传统技术相比，所有数字化印模组在准确性方面都表现出更好的数据。DC 组在距离和角度测量方面具有最高的准确性。本体外研究结果表明，在高角度的全颌种植病例中，与传统印模技术相比，口内扫描仪的使用更具优势。
