The effect of wire alloy on torque expression in metallic self-ligating orthodontic brackets.

摘要

The objective of this thesis was to identify differences in torque expression between three brands of metallic self-ligating brackets with stainless steel, TMARTM and CuNiTiRTM wire and to compare active and passive designs. 150 of each Damon-3MX (Ormco Inc, Orange, CA, USA), SPEED (Strite Industries, Cambridge, Ontario, Canada) and In-Ovation-R (GAC, Bohemia, NY, USA) brackets were measured for torque expression (Nmm) in an Air-shields IsoletteRTM infant incubator. Torque expression in SPEED and In-Ovation-R brackets began at approximately 7.5° vs. 12° with Damon-3MX. Clinically applicable torque expression (5-20Nmm) was observed from approximately 15-30° in SPEED & In-Ovation-R brackets with stainless steel wire. In Damon-3MX, comparable torsional moments were expressed from 18-30°. With TMA wire, SPEED exerted clinically applicable torsional moments from 18-39°, In-Ovation-R from 21-39° and Damon-3MX from 21-42°. For CuNiTi wire, SPEED expressed torsional moments of 5-20Nmm from 21-72°, In-Ovation-R from 24-63° and Damon-3MX from 27-78°.