Longitudinal evaluation of extraction space closure, at final, medium and long-term, and its association with the adopted protocol, in patients treated in the last 40 years, with several initial malocclusions

• Ano de defesa: 2019
• Autor(a) principal: Valerio, Marcelo Vinicius
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Extração dentária; Extraction; Fechamento de espaço ortodôntico; Má oclusão; Malocclusion; Orthodontic space closure
• Link de acesso: http://www.teses.usp.br/teses/disponiveis/25/25144/tde-04092019-201838/

Introduction: This study aimed to evaluate and quantify extraction spaces and their behavior at the end of treatment, short- and long-term stages, in orthodontic patients treated with extractions. Methods: The sample comprised dental casts of 1546 orthodontic patients treated with extractions with several malocclusions. Dental casts were divided into 3 groups, according to the chronological stage: at the end of treatment (T0), 1-year posttreatment (short-term, T1) and 5-year posttreatment (longterm, T2). Extraction spaces were measured in the three stages with a digital caliper. The descriptive analyses of the longitudinal space behavior were performed by amounts of patients, percentage of patients and percentage of quadrants. Intergroups comparison of space dimension in the three stages were performed by Analysis of Variance, followed by Tukey tests when necessary. Results: Class II malocclusion was the most prevalent sagittal discrepancy, followed by Class I and Class III, respectively. More than a half of the patients presented 1-4 quadrants open at the end of treatment. Less than 10% of quadrants persisted open at the three stages. Most of relapse and late closure occurred in the first year after treatment. About 5% of quadrants closed at T0 presented relapse at T1. Less than 3% of quadrants closed at T1 presented relapse at T2. Space dimension decreased significantly in the long-term evaluation. Conclusions: The percentage of patients with open spaces at the end of treatment was substantially large. Despite of the late space closure tendency, several spaces may remain open in the long-term. There was significant reduction in extraction space dimension in the long-term.