Longterm stability of posterior crossbite correction after rapid maxillary expansion with the fan-type and differential expanders

• Grant number: 25/11515-9
• Support Opportunities: Scholarships in Brazil - Master
• Start date: November 01, 2025
• End date: February 28, 2027
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Principal Investigator: Camila da Silveira Massaro
• Grantee: Amanda Lopes
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

Introduction: The fan-type expander (FE) and the expander with differential opening (EDO) are indicated for rapid maxillary expansion in cases with greater constriction in the anterior region of the upper dental arch. However, the stability of the outcomes has not been evaluated. Objective: Therefore, the purpose of this study will be to evaluate the stability of the correction of the posterior crossbite after treatment with EDO and FE expanders. Material and Methods: A longitudinal observational study will be conducted, derived from a previous randomized clinical trial (NCT03705871), which compared the dentoskeletal effects of the EDO and the FE. A total of 48 individuals of both sexes, aged between 7 and 11 years and presenting with posterior crossbite at the beginning of treatment, will be included. These patients will be followed for at least five years after expansion with either the EDO (n=24) or the FE (n=24). The control group will consist of 24 untreated individuals followed over the same time interval. The presence of posterior crossbite and the dental arch dimensions (width, perimeter, length, shape, and size) will be evaluated using digital dental models using the software 3D Slicer, OrthoAnalyzer, Stratovan Checkpoint, and MorphoJ. After normality test, intra- and intergroup comparisons will be performed with analysis of variance (ANOVA), using the Jamovi software (P<0.05). Keywords: Interceptive Orthodontics; Dental Models; Longitudinal Studies; Palatal Expansion Technique; 3D Imaging.