Comparison of deformation and torque expression of the orthos and orthos Ti bracket systems

Abstract

Orthodontic torque expression is the result of axial rotation of rectangular archwires within a rectangular bracket slot. This study investigates the effect of bracket material on torque expression. Torque exerted by a rotating archwire on each bracket will be measured as well as the relative deformation of each bracket slot. A total of 60 tests were performed where archwires were rotated within a bracket slot to produce torque within a bracket. Thirty Ormco Orthos Ti and 30 Orthos SS were compared to investigate the effect of torque on bracket material. Each bracket was mounted on a six-axis load cell that measured forces and moments in all directions. The archwire was rotated from an initial angle of 0 degree in 3 degrees increments to maximum angle of 51 degrees and then returned to the initial position. An overhead camera took images at each 3 degrees increment. The bracket images were post-processed using a digital image correlation technique to measure the relative deformation of each bracket slot. The maximum torque expressed at 51 degrees was 99.8 Nmm and 93.0 Nmm for Orthos Ti and Orthos SS, respectively. Total plastic deformation measured at 0 degrees post-torquing of the Orthos SS was 0.038 mm compared to 0.013 mm for Orthos Ti. The Orthos Ti brackets plastically deformed less than the Orthos SS brackets after torquing. The Orthos SS bracket plastic deformation was 2.8 times greater than that of Orthos Ti brackets. The Orthos Ti brackets expressed more torque than the stainless steel brackets but exhibited substantial variation.

Three-dimensional deformation of orthodontic brackets

“…5–8 The addition of a second camera to the OTS allows for the measurement of the z * displacement. Deformation of the orthodontic bracket was measured by post processing a sequence of stereo images collected using the OTS.…”

“…5 Subsequently, the OTS was used to measure deformation of a variety of conventional and self-ligated brackets. 6–8 …”

“…Deformation measurements using a single camera 5–8 can only measure surface in-plane motion of the bracket; out-of-plane motion and deformation measurements require a minimum of two cameras. 14 The ability to measure three-dimensional (3D) deformation of the orthodontic bracket will enable the interaction of the archwire–bracket to be fully described using three-dimensional digital image correlation (3D DIC).…”

Analyse der Torquekapazität einer vollständig individuellen lingualen Apparatur (WIN)

“…8 Vergleich der Torquecharakteristika der in der vorliegenden Studie untersuchten 0,0175 × 0,0175″ β-Titaniumdrähte (mit Quadraten markierte Linien) mit den von Sifakakis et al [18] präsentierten Daten zur gleichen Drahtqualität und -dimension gemessen in einer Incognito™ Apparatur. [29,30]. Zusätzlich wurden auch Friktion und Binding sowie eine Abschrägung der Kanten des Bogens und eine Auf wölbung des Slotprofiles als Erklärungsmöglichkeiten angeführt [18].…”

Avaliação da profundidade da canaleta dos bráquetes autoligados passivos associados à expressão do torque

“…(Lacoursiere et al, 2010;Major et al, 2010;Major et al 2011). Outro fator que também pode estar relacionado é o desenho da canaleta do bráquete, e sua composição metálica (Melenka, et al, 2014;Major et al, 2013). A escolha do bráquete a ser empregado no tratamento, o conhecimento de como este material com maior ou menor dureza comporta-se durante o tratamento é de fundamental importância para conduzi-lo (Fischer-Brandies et al, 2000;Gioka;Eliades, 2004).…”