Reliability of Stereophotogrammetric Soft Tissue Measurements Compared to Cone-Beam Computed Tomography

• Grant number: 25/11149-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Principal Investigator: Felicia Miranda
• Grantee: Mariana Luri Catuyama Marques
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

Introduction: Three-dimensional stereophotogrammetry (SPG) has emerged as a promising alternative for facial analysis in Orthodontics, as it is a non-invasive, radiation-free, and easily accessible technique. However, evidence regarding its reliability compared to well-established methods, such as cone-beam computed tomography (CBCT), remains scarce. Objective: This study aims to compare the reliability of soft tissue facial measurements obtained through stereophotogrammetry and CBCT. Materials and Methods: The sample will consist of three-dimensional scans from 22 patients, aged between 15 and 20 years, treated at the Orthodontic Clinic of the Bauru School of Dentistry -University of São Paulo (USP). SPG and CBCT scans will be evaluated using the 3D Slicer software (www.slicer.org). Three-dimensional models of the facial soft tissue will be obtained from CBCT via automatic segmentation. The 3D measurements will include horizontal linear variables (such as intercanthal distance, bizygomatic width, and intercommissural distance), vertical variables (heights of the facial thirds and total facial height), as well as maxillary depth. Statistical analysis will include the intraclass correlation coefficient (ICC), Bland-Altman plots, and paired comparison tests. The significance level will be set at 5%. It is expected that the results will show high agreement between the two techniques, validating stereophotogrammetry as a reliable tool for three-dimensional facial analysis in orthodontic practice.