Volumetric assessment of tooth roots in patients undergoing dentoalveolar expansion with orthodontic aligners

• Grant number: 25/05716-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2025
• End date: May 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Principal Investigator: Maria Bernadete Sasso Stuani
• Grantee: Victor Ramos da Cruz
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Introduction: Dentoalveolar expansion consists of re-establishing the transverse dimension of the dental arch and can contribute, among other things, to diluting crowding by increasing the perimeter of the arch. By generating tension in the dental apex, this procedure can predispose to the appearance of external apical root resorption (EARR) with consequent loss of root volume. The literature is still controversial as to the possibility of a lower incidence of EARR from dentoalveolar expansions treated with orthodontic aligners, when compared to those made with fixed appliances. Aim: To use cone beam computed tomography (CBCT) scans to assess the root volume of maxillary incisors in patients undergoing dentoalveolar expansion with orthodontic aligners and its possible alteration with the degree of crown vestibuloversion after the procedure. Material and Method: The study sample consisted of CBCT orthodontic documentation of 51 adult patients with no residual growth, from a private clinic in the city of Sorocaba, São Paulo, Brazil. The individuals had constricted upper dental arches and were treated with dentoalveolar expansion using Invisalign® orthodontic aligners for an average period of 19 months. The CBCT images will be analyzed retrospectively at two points in time: T0 (before treatment) and T1 (after treatment). The root volumes of maxillary central and lateral incisors will be assessed using three-dimensional surface models obtained through the semi-automatic CBCT image segmentation technique. The inclinations of the dental crowns will be evaluated at the two times described. The pre-treatment (T0) and post-treatment (T1) measurements will be subjected to the normality test and parametric or non-parametric tests will be used at a 5% significance level to identify differences between the means. The relationship between root volume loss and the degree of tooth inclination will be assessed using multiple linear regression. (AU)