Influence of rescanning mesh holes on the accuracy of an intraoral scanner: An in vivo study.

Abstract Objectives To evaluate whether the cutting-off and rescanning procedures have an impact on the accuracy (trueness and precision) of the intraoral digital scan. Methods A right quadrant digital scan (reference scan) of a participant was obtained using an intraoral scanner (IOS) (TRIOS 4; 3Shape A/S, Copenhagen, Denmark). The reference scan was duplicated 135 times and divided into 3 groups based on the number of rescanned mesh areas: 1 (G1 group), 2 (G2 group), and 3 (G3 group) mesh holes. Each group was subdivided into 3 subgroups depending on the mesh hole diameter: 2 mm- (G1–2, G2–2, and G3–2), 4 mm- (G1–4, G2–4, and G3–4), and 6 mm- (G1–6, G2–6, and G3–6) (n = 15). A software program (Geomagic; 3D Systems, Rock Hill, SC, USA) was used to assess the discrepancy between the reference and the experimental scans using the root mean square (RMS). Kruskal-Wallis and post hoc multiple comparison Dunn's tests were used to analyze the data (α=0.05). Results Trueness ranged from 5 to 20 µm and precision ranged from 2 to 10 µm. For trueness assessment, Kruskal-Wallis test revealed significant differences on the RMS error values among the groups tested (P Conclusions Cutting-off and rescanning procedures decreased the accuracy of the IOS tested. The higher the number and diameter of the rescanned areas, the lower the accuracy. Clinical significance Cutting-off and rescanning procedures should be minimized in order to increase the accuracy of the IOS evaluated. The intended clinical use of the intraoral digital scan is a critical factor that might determine the scanning workflow procedures.