Evaluating point cloud density, surface topography, and accuracy across six extraoral scanners: A correlational and 3-dimensional (3D) comparative study.

Abstract

<h4>Statement of problem</h4>Accurate digital scans are critical for clinically acceptable restorations, yet the influence of point cloud density and mesh topology on dimensional fidelity remains unclear.<h4>Purpose</h4>The purpose of this in vitro study was to compare 6 extraoral scanners (EOSs) in terms of trueness, precision, and surface morphology and to examine the relationship between geometric density metrics and coordinate-specific deviations.<h4>Material and methods</h4>A mandibular complete arch model with 5 abutments was scanned using 6 devices (10 scans each). A calibrated industrial structured-light scanner (ATOS Core 200) served as the reference device. Trueness (RMS), precision, point density, triangle count, and axis-specific deviations were analyzed with Geomagic and CloudCompare. Statistical tests included nonparametric analyses, 3-way ANOVA, and Spearman correlations (α=.05).<h4>Results</h4>Significant differences were found among scanners (P<.05). DOF showed the highest trueness, E3 highest precision, and MEDIT lowest performance. Mesh density correlated weakly with accuracy. Z-axis deviations exceeded X and Y (P<.001).<h4>Conclusions</h4>All scanners met clinical thresholds, but device-specific differences and vertical errors should be considered in complete arch applications.