Comparative evaluation of novel framework-supported 3-dimensional facial scanning using smartphone device with freehand facial scanning in patients seeking orthodontic treatment: A cross-sectional study.

INTRODUCTION

Surface anthropometric assessment of soft tissues is an ideal approach for measuring 3D facial changes with smartphone/tablet-based applications revolutionizing 3D facial acquisition. However, the scans obtained are prone to distortion and have limited repeatability due to the freehand recording of the scans in continuous image capture mode, thus also reducing their reliability. The aim was to introduce the design and operation of an innovative apparatus for acquiring 3D facial scans in a standardised, repeatable, and convenient way for young children and adults.

MATERIAL AND METHODS

The apparatus presents a framework with a straight and scissor arm with the recommended dimension of 68×60×34cm with a 360-degree rotatory joint similar to wall-mounted X-ray systems used in dental offices. Facial scans of 15 patients aged between 19-25 years (mean age=23.13 years) were recorded using the two techniques (framework-supported [SF] and freehand [SWF]) Scandy Pro app in Apple iPad Pro. The scans were exported in .stl format and analysed using Meshlab and Viewbox 4 software for surface comparison, scan time, and mean absolute distance (MAD) between facial soft tissue landmarks.

RESULTS

Scans using the framework (SF) showed fewer aberrations, especially in the nasolabial and periorbital areas. Zygoma R and L (0.608±1.605 and 0.503±1.191 respectively) displayed the most difference, while Point A (0.323±1.381), Pogonion (0.364±1.344), and infraorbital region R and L (0.307±0.785 and 0.362±1.089 respectively) displayed the least. With no scan interruptions, the average scan time decreased threefold to 10.14seconds for SF compared to 27.81seconds for SWF, with 12 instances of tracking loss. Superimposition analysis of SF scans shows ICC values from 0.574 to 0.882, indicating good agreement.

CONCLUSION

The proposed framework provides a reliable, accurate, and cost-effective alternative for 3D facial imaging using smartphone devices. It demonstrates high reproducibility and significant reductions in scan time and tracking loss. This apparatus could facilitate the routine clinical use of 3D facial scanning in orthodontics, offering portable and non-invasive solutions.