College of Dentistry, Texas A&M University, Dallas, TX.
Department of Prosthodontics, School of Dentistry, University of Washington, Seattle, WA.
J Prosthodont. 2020 Feb;29(2):107-113. doi: 10.1111/jopr.13135. Epub 2019 Dec 30.
To quantify the impact of ambient lighting conditions on the accuracy (trueness and precision) of an intraoral scanner (IOS) when maxillary complete-arch and maxillary right quadrant digital scans were performed in a patient.
One complete dentate patient was selected. A complete maxillary arch vinyl polysiloxane impression was obtained and poured using Type IV dental stone. The working cast was digitized using a laboratory scanner (E4 Dental Scanner; 3Shape) and the reference standard tessellation language (STL file) was obtained. Two groups were created based on the extension of the maxillary digital scans performed namely complete-arch (CA group) and right quadrant (RQ) groups. The CA and RQ digital scans of the patient were performed using an IOS (TRIOS 3; 3Shape) with 4 lighting conditions chair light (CL), 10 000 lux, room light (RL), 1003 lux, natural light (NL), 500 lux, and no light (ZL), 0 lux. Ten digital scans per group at each ambient light settings (CL, RL, NL, and ZL) were consecutively obtained (n = 10). The STL file was used to analyze the discrepancy between the digitized working cast and digital scans using MeshLab software. Kruskal-Wallis, one-way ANOVA, and pair-wise comparison were used to analyze the data.
Significant difference in the trueness and precision values were found across different lighting conditions where RL condition obtained the lowest absolute error compared with the other lighting conditions tested followed by CL, NL, and ZL. On the CA group, RL condition also obtained the best accuracy values, CL and NL conditions performed closely and under ZL condition the mean error presented the highest values. On the RQ group, CL condition presented the lowest absolute error when compared with the other lighting conditions evaluated. A pair-wise multicomparison showed no significant difference between NL and ZL conditions. In all groups, the standard deviation was higher than the mean errors from the control mesh, indicating that the relative precision was low.
Light conditions significantly influenced on the scanning accuracy of the IOS evaluated. RL condition obtained the lowest absolute error value of the digital scans performed. The extension of the digital scan was a scanning accuracy influencing factor. The higher the extension of the digital scan performed, the lower the accuracy values obtained. Furthermore, ambient light scanning conditions influenced differently depending on the extension of the digital scans made.
量化环境光照条件对口腔内扫描仪（IOS）准确性（准确性和精密度）的影响，当在患者中进行上颌全弓和上颌右象限数字扫描时。
选择了一位完全无牙的患者。获得了完整的上颌牙槽硅橡胶印模，并使用 IV 型牙科石膏进行浇铸。工作模型使用实验室扫描仪（E4 Dental Scanner；3Shape）进行数字化，并获得参考标准镶嵌语言（STL 文件）。根据上颌数字扫描的扩展创建了两组，即全弓（CA 组）和右象限（RQ）组。使用 IOS（TRIOS 3；3Shape）以 4 种照明条件（椅灯（CL）、10,000 勒克斯、室灯（RL）、1,003 勒克斯、自然光（NL）、500 勒克斯和无光（ZL）、0 勒克斯）对患者进行 CA 和 RQ 数字扫描。在每个环境光设置（CL、RL、NL 和 ZL）下连续获得每组 10 个数字扫描（n=10）。使用 MeshLab 软件分析 STL 文件，以分析数字化工作模型与数字扫描之间的差异。使用 Kruskal-Wallis、单因素方差分析和两两比较分析数据。
不同照明条件下，准确性和精密度值存在显著差异，其中 RL 条件下的绝对误差最低，其次是 CL、NL 和 ZL。在 CA 组中，RL 条件也获得了最佳的准确性值，CL 和 NL 条件接近，而在 ZL 条件下，平均误差最高。在 RQ 组中，与评估的其他光照条件相比，CL 条件下的绝对误差最低。两两多重比较显示，NL 和 ZL 条件之间没有显著差异。在所有组中，标准偏差均高于对照网格的平均误差，表明相对精度较低。
光照条件对 IOS 的扫描准确性有显著影响。RL 条件下获得的数字扫描绝对误差值最低。数字扫描的扩展是影响扫描准确性的因素。数字扫描的扩展越大，获得的准确性值越低。此外，环境光扫描条件的影响因数字扫描的扩展而不同。
