Force system evaluation of symmetrical beta-titanium T-loop springs preactivated by curvature and concentrated bends.

Abstract

INTRODUCTION:

The objective of this research was to compare the effect of preactivation on the force system of beta-titanium T-loop springs (TLSs).

METHODS:

Twenty TLSs with dimensions of 6 × 10 mm, of 0.017 × 0.025-in beta-titanium alloy, were randomly divided into 2 groups according to their preactivation. By using a moment transducer coupled to a digital extensometer indicator adapted to a testing machine, the amounts of horizontal force and moment produced were recorded at every 0.5 mm of deactivation from 5 mm of the initial activation in an interbracket distance of 23 mm. The moment-to-force ratio, the "neutral position" and the load-deflection ratio were also calculated.

RESULTS:

TLSs preactivated by curvature delivered horizontal forces significantly lower than those preactivated by concentrated bends. No differences were found in relation to the moments produced throughout the deactivation of both groups. The moment-to-force ratios were systematically higher on the TLSs preactivated by curvature than those preactivated by concentrated bends, except on 5 mm of activation. Significant differences were found in the load-deflection rates and "neutral position."

CONCLUSIONS:

The TLSs preactivated by curvature delivered lower horizontal forces and higher moment-to-force and load-deflection ratios than did those preactivated by concentrated bends.

• Authors: Sergei Godeiro Fernandes Rabelo Caldas, Renato Parsekian Martins, Marília Regalado Galvão, Camilla Ivini Viana Vieira, Lídia Parsekian Martins
• Journal: American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics (Am J Orthod Dentofacial Orthop) Vol. 140 Issue 2 Pg. e53-8 (Aug 2011) ISSN: 1097-6752 [Electronic] United States
• PMID: 21803234 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Chemical References

• Dental Alloys
• beta titanium
• Titanium

Topics

• Dental Alloys
• Dental Stress Analysis
• Materials Testing
• Orthodontic Appliance Design
• Orthodontic Space Closure (instrumentation)
• Orthodontic Wires
• Random Allocation
• Stress, Mechanical
• Titanium