Background: Three-dimensional (3D) photogrammetry has reached high standards and accuracy but is mainly conducted with stationary and expensive systems. The purpose of this study was to evaluate the accuracy of a low-budget portable system with special regard to the gracile and challenging nasal region.
Material and methods: 3D models of the perinasal area were acquired by impression-taking and the scanning of the generated plaster models (3Shape D500) or with a portable low-budget 3D stereophotogrammetry (FUEL3D® SCANIFY®) system. Four examiners analysed defined landmarks of the generated Standard Tessellation Language files with regard to accuracy and interobserver reliability by using 3dMDvultus™ software. A semi-automatic 3D best-fit analysis of both models was performed by using Geomagic® and the Root Mean Squared (RMS) errors were calculated.
Results: 41 volunteers were included, with 22 perinasal and perioral landmarks, 15 3D distances and eight 3D angles being analysed per data set. In a point-based analysis the mean spreads were partially smaller in the plaster model scans. Most measurements showed very high (>0.8) to excellent (>0.9) intraclass correlation coefficients, the lowest being found for columella length (0.686) and left nostril width (0.636). Overall, the mean RMS error between the superimposed surfaces was 0.89 ± 0.22 mm in the best-fit analysis.
Conclusions: The corresponding software program was operator-friendly. The findings indicate that the analysed, affordable and portable system is a feasible solution for 3D image acquisition with comparable accuracy reported in the literature. Further studies will analyse the feasibility in neonates.
Keywords: CAD/CAM nasoalveolar molding; Nose; Portable facial scanner; Three-dimensional stereophotogrammetry.
Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.