Department of Prosthodontics, Faculty of Dentistry, Istinye University, Istanbul, Turkey; Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
J Dent. 2023 Nov;138:104736. doi: 10.1016/j.jdent.2023.104736. Epub 2023 Oct 5.
To evaluate the suitability of intraoral scanners (IOSs) to analyze the fabrication trueness of titanium complete-arch implant-supported frameworks by comparing with an industrial-grade scanner and investigate how anti-reflective scan powder affects measured deviations.
Ten titanium complete-arch implant-supported frameworks were milled from a reference standard tessellation language (STL) file. An industrial-grade blue light scanner (ATOS Core 80 (AT)) and three IOSs (Primescan (PS), TRIOS T3 (T3), and TRIOS T4 (T4)) with (PS-P, T3-P, and T4-P) or without (PS, T3, and T4) anti-reflective scan powder application were used to generate test STL (TSTL) files of the frameworks. Reference STL and TSTLs were imported into a metrology-grade analysis software (Geomagic Control X) and whole surface root mean square (RMS) values were calculated. Another software (Medit Link v 2.4.4) was used to virtually isolate marginal surfaces of all STL files and marginal RMS values were calculated by using the same metrology-grade analysis software. A linear mixed effects model was used to compare the transformed deviations of the scans performed by using each IOS (with or without powder) with the deviations of those performed by using the reference AT scanner within each surface, where a Box-Cox type transformation was used for variance stability. Bonferroni corrected post-hoc tests were used to compare conditions within each IOS (α=0.05).
All IOSs had significantly higher whole surface and marginal RMS values than AT, regardless of the condition (P≤.002). However, scan powder application did not affect the whole surface and marginal RMS values in scans of tested IOSs (P≥.054).
Measured whole surface and marginal deviations in all IOS scans performed with or without the use of scan powder were higher than those in AT scans. The application of anti-reflective scan powder did not affect the deviations in scans of tested IOSs.
Even though deviations measured in the scans of tested scanners were significantly different than those in the reference scanner, the maximum raw mean difference was 37.33 µm and the maximum raw confidence interval value of estimated differences was 47.88 µm, which can be considered clinically small taking into account the size of the frameworks tested. Therefore, tested intraoral scanners may be feasible to scan prostheses similar to or smaller than tested frameworks for fabrication trueness analysis, which may facilitate potential clinical adjustments.
通过与工业级扫描仪进行比较，评估口内扫描仪（IOS）分析钛全口种植体支持框架制作精度的适用性，并研究抗反射扫描粉末如何影响测量偏差。
从参考标准 tessellation language（STL）文件中铣削出 10 个钛全口种植体支持框架。使用工业级蓝光扫描仪（ATOS Core 80（AT））和三个 IOS（Primescan（PS）、TRIOS T3（T3）和 TRIOS T4（T4））（PS-P、T3-P 和 T4-P）或无抗反射扫描粉末应用（PS、T3 和 T4）生成框架的测试 STL（TSTL）文件。将参考 STL 和 TSTL 导入计量级分析软件（Geomagic Control X），并计算整体表面均方根（RMS）值。另一个软件（Medit Link v 2.4.4）用于虚拟隔离所有 STL 文件的边缘表面，并使用相同的计量级分析软件计算边缘 RMS 值。使用线性混合效应模型比较每个 IOS（有或无粉末）扫描的转换偏差与参考 AT 扫描仪在每个表面内的偏差，其中使用 Box-Cox 类型转换进行方差稳定性。使用 Bonferroni 校正后检验比较每个 IOS 内的条件（α=0.05）。
无论条件如何（P≤.002），所有 IOS 的整体表面和边缘 RMS 值均明显高于 AT。然而，扫描粉末的应用并不影响测试 IOS 扫描的整体表面和边缘 RMS 值（P≥.054）。
使用或不使用扫描粉末进行的所有 IOS 扫描的测量整体表面和边缘偏差均高于 AT 扫描。抗反射扫描粉末的应用并未影响测试 IOS 扫描的偏差。
即使测试扫描仪的测量偏差与参考扫描仪明显不同，但最大原始平均差值为 37.33 µm，估计差值的最大原始置信区间值为 47.88 µm，考虑到测试框架的大小，这可以认为是临床较小的差异。因此，测试的口内扫描仪可能适用于扫描类似于或小于测试框架的修复体，以进行制作精度分析，这可能有助于潜在的临床调整。
