Deformation of metal brackets: a comparative study
The purpose of this study was to determine the effect of material and design on the force and stress required to permanently deform metal brackets. Fourteen types of metal brackets were categorized according to raw material composition, slot torque degree, and wing type. Five types of raw materials, three types of slot torque degree, and four types of wing design were tested using an archwire torque test developed by Flores. An analysis of variance (ANOVA) and t-test showed that all three categories had a significant effect on the force and stress needed to permanently deform metal brackets. Of the three, raw material had the greatest effect on the amount of force. Results showed that 17-4PH and 303S had higher yield strengths and regular twin brackets had higher resistance to deformation. Also, as slot torque degree increased, brackets deformed with less force. Result confirmed that brackets requiring the greatest stress to permanently deform were made of steel with the greatest hardness.Abstract
Contributor Notes
D. A. Flores is an Assistant Professor of Orthodontics, Loma Linda University, Loma Linda, California
L. K. Choi is in private practice in Anaheim, California. This article is from a thesis submitted in partial fulfillment of the requirements for a Master of Science degree
J. M. Caruso is an Associate Professor of Orthodontics, Loma Linda University, Loma Linda, California
J. L. Tomlinson is a Professor in the Department of Orthodontics, Loma Linda University, Loma Linda, California
Garland E. Scott is a Professor in the Department of Orthodontics, Loma Linda University, Loma Linda, California
M. Toufic Jeiroudi is Director and Professor of Orthodontics, Loma Linda University, Loma Linda, California