Comparative evaluation of mesh density and 3D accuracy in stationary, handheld, and mobile facial scanning systems: an in vitro study.

Abstract

<h4>Objective</h4>This in vitro study evaluated mesh density and 3D accuracy of three facial scanning systems: a stationary scanner, a handheld scanner, and a mobile scanning application.<h4>Methods</h4>A mannequin head with 14 fixed landmarks across three facial regions served as the master model. An industrial scanner (ATOS Q, Zeiss Co.) was used as reference. The three evaluated systems included a stationary scanner (RAYFace v2.0, Ray Co.), a handheld scanner (Metismile, Shining 3D), and a mobile application (Heges, Marek Simonik) on a smart device (iPad Pro X, Apple Inc.). Each system acquired 20 scans. Mesh density (polygons/mm²) and 3D accuracy (via surface deviation and RMS error) were analyzed. Statistical analysis included the Shapiro-Wilk test, two-way repeated ANOVA, and post hoc tests (Tukey, Welch, Tamhane) (α = .05).<h4>Results</h4>Mesh density (polygons/mm²) varied significantly: handheld (13.51 ± 0.26), mobile (11.57 ± 0.08), and stationary (1.88 ± 0.15). The handheld scanner demonstrated the highest trueness (0.70 ± 0.19 mm) and precision (0.27 ± 0.12 mm). The mobile scanner exceeded the clinical trueness threshold (1.12 ± 0.27 mm) in the lower face. The stationary scanner showed the lowest precision (0.64 ± 0.11 mm). Significant differences were found in trueness (p = .004), precision (p = .001), and among facial regions (p < .001).<h4>Conclusions</h4>While global trueness (RMS < 1 mm) was achieved across all systems, accuracy varied significantly by facial region. The handheld scanner demonstrated the highest overall performance. The stationary scanner, despite its lower mesh density, maintained acceptable trueness but exhibited reduced precision in the lower facial region. These findings underscore the importance of evaluating both mesh density and regional accuracy when selecting facial scanners for clinical use.<h4>Clinical significance</h4>The handheld scanner is preferred for optimal mesh density and trueness, though it requires more time and reduces patient comfort. The stationary scanner offers lower mesh density but acceptable trueness and limited precision in the lower face. The mobile scanner is a cost-effective alternative, though it compromises trueness and precision.