Comparative evaluation of the force exerted on the deflection of orthodontic wires in conventional brackets fixed by different modes of binding and in self ligation

• Grant number: 13/10378-0
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): October 01, 2013
• Effective date (End): February 28, 2015
• Field of knowledge: Health Sciences - Dentistry - Orthodontics
• Principal Investigator: José Fernando Castanha Henriques
• Grantee: Rodrigo Hitoshi Higa
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

The aim of the study will be the evaluation of the deflection of orthodontic wires of round section of 0.014-inch and 0.016-inch on conventional brackets (Morelli), fixed by three modes of binding ("O" shaped elastomeric ligatures, "X" shaped elastomeric ligatures and "O" shaped metal ligatures), and self-ligating brackets (Morelli, Bioquick and Damon Q). Two different alloys will be used: conventional nickel-titanium and thermally activated nickel-titanium. The specimens will be assembled in a clinical simulation model, specially designed for this study, and evaluated in a Universal Testing Machine (Instron), following protocol as ISO 15,841. In an acrylic resin plate 14 devices will be attached and the brackets will placed on them. The intention is attach these devices in resemblance to the positioning of teeth in the upper dental arch, in the form of a parabola. The interval of space between them will be kept constant to avoid errors during the measurement of the force generated by the deflection of the wires. For the procedures of the testing, the acrylic device representative of the right central incisor will be moved lingually, with readings of the resistance generated by the deflection at 1, 2 and 3mm with constant speed of 2mm/min. After the deflection tests, the results will be evaluated by analysis of variance (ANOVA) to one or more criteria, with a significance level of 5% (p <0.05) for comparison between groups. In the case of significant difference, the comparative analysis of the averages will be perform made by using the Tukey test (p <0.05). (AU)