Talwar Aditya, Duggal Isha, Grewal Harpreet, Bhutiani Neha, Singh Navneet, Kaushik Saurabh
Orthodontics & Dentofacial Orthopaedics, Manav Rachna Dental College, Faridabad, India.
AIIMS-CAPFIMS, New Delhi, India.
Int Orthod. 2025 Sep;23(3):101012. doi: 10.1016/j.ortho.2025.101012. Epub 2025 Apr 25.
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.
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.
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.
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.
软组织的表面人体测量评估是测量三维面部变化的理想方法，基于智能手机/平板电脑的应用彻底改变了三维面部采集方式。然而，由于在连续图像捕捉模式下扫描是徒手记录的，所获得的扫描容易出现失真且重复性有限，从而也降低了其可靠性。本研究的目的是介绍一种创新设备的设计与操作，该设备能以标准化、可重复且便捷的方式为儿童和成人获取三维面部扫描。
该设备呈现出一个带有直臂和剪式臂的框架，推荐尺寸为68×60×34厘米，具有一个360度旋转关节，类似于牙科诊所使用的壁挂式X射线系统。使用苹果iPad Pro中的Scandy Pro应用程序，通过两种技术（框架支撑[SF]和徒手[SWF]）记录了15名年龄在19 - 25岁之间（平均年龄 = 23.13岁）患者的面部扫描。扫描结果以.stl格式导出，并使用Meshlab和Viewbox 4软件进行分析，以比较面部软组织标志点之间的表面、扫描时间和平均绝对距离（MAD）。
使用框架（SF）进行的扫描显示出较少的畸变，尤其是在鼻唇沟和眶周区域。右侧和左侧颧骨（分别为0.608±1.605和0.503±1.191）的差异最大，而点A（0.323±1.381）、颏前点（0.364±1.344）以及右侧和左侧眶下区域（分别为0.307±0.785和0.362±1.089）的差异最小。在没有扫描中断的情况下，SF的平均扫描时间降至10.14秒，是SWF的27.81秒的三分之一，SWF有12次跟踪丢失情况。SF扫描的叠加分析显示ICC值在0.574至0.882之间，表明一致性良好。
所提出的框架为使用智能手机设备进行三维面部成像提供了一种可靠、准确且经济高效的替代方案。它显示出高再现性，并显著减少了扫描时间和跟踪丢失情况。该设备可促进正畸学中三维面部扫描的常规临床应用，提供便携式和非侵入性解决方案。
