Long-term effects of the treatment with function regulator Fr-2: evaluation 6 years post-retention

• Grant number: 10/14997-9
• Support Opportunities: Scholarships abroad - Research
• Start date: September 05, 2011
• End date: June 04, 2012
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Principal Investigator: Fernanda Angelieri
• Grantee: Fernanda Angelieri
• Host Investigator: James A. McNamara
• Host Institution: Pró-Reitoria de Pós-Graduação e Pesquisa. Universidade Metodista de São Paulo (UMESP). Instituto Metodista de Ensino Superior (IMS). São Bernardo do Campo , SP, Brazil
• Institution abroad: University of Michigan, United States

Abstract

The Function Regulator (FR-2) of Fränkel has been indicated to the treatment of retrusive Class II malocclusions. However, its skeletal effects are controversial, mainly in relation to the increase of the mandibular length. Moreover, few studies have evaluated the stability of these effects over a long term. The aim of the present study is to examine the skeletal and dentoalveolar changes promoted by RF-2 appliance and their permanence after 6.61 years post-retention. Methods: The RF-2 group is prospective, composed by 18 patients (10 boys and 8 girls), with Class II division 1 malocclusion, mean initial age of 10.77 years (T1), treated exclusively with the Fränkel-2 Function Regulator appliance during 1.5 year (T2) and followed by nocturnal wear during 6 months for retention. These patients were reevaluated after a mean post-retention period of 6.61 years (T3). The control group will be comprised by patients with untreated Class II malocclusion, matched the RF-2 group (initial, final and post-treatment ages, sex and skeletal maturation), and obtained from the University of Michigan Growth Study and the Denver Child Growth Study. Lateral cephalograms of both groups will be analyzed with a specific tracing regimen in the T1, T2 and T3 phases. To compare the starting forms (T1) and the changes between the two groups in the treatment (T1-T2), post-treatment (T2-T3) and long-term (T1-T3) periods, it will be utilized the Student t test (p<0.05). (AU)