Corrosion of Orthodontic Wires According to Heat Treatment Conditions

Abstract

Heat treatments are applied to orthodontic wires in order to relieve the stresses arising during orthodontic work. Four types of wires were heated in air, argon or vacuum environments, and cooled in the furnace or in a water bath. The susceptibility to corrosion and mechanical properties of the heat-treated wires were investigated. Heat treatment marginally increased the yield strength and elastic modulus of all wires. After heat treatment in air, both water-and furnace-cooled wires had similar low corrosion resistances. Corrosion resistances of wires heated under vacuum differed significantly according to cooling methods, such that furnace-cooled wires had higher corrosion resistances than watercooled wires. Water-cooled wires consistently showed low corrosion resistance whether heated in vacuum, argon, or air environments. After heat treatment under vacuum, furnace-cooled wires had low current densities and high pitting potentials similar to control wires, but other heattreated wires generally exhibited high current densities and low pitting potentials. Wires heat-treated under vacuum or argon and then cooled in the furnace were the least susceptible to surface oxidation and corrosion, and showed a marginal improvement in mechanical properties. Therefore, we conclude that wires treated in these way can reduce metal ion release and wire fracture, which can minimize adverse effects arising from orthodontic practices.

Corrosion resistance and mechanical properties of titanium nitride plating on orthodontic wires

“…However, it is unlikely that the TiN layer mainly leads to these results, because it is a thin layer. Several studies have reported that mechanical properties of SS and Ni-Ti wires are changed by heating treatment [18][19][20][21] . In this study, orthodontic wires were heated at 220°C for 7 min for TiN coating.…”

Investigation on Corrosion Behaviour of Copper Brazed Joints

“…To investigate the corrosion properties of the samples, potentiodynamic testing was performed on 1cm_long samples in sea water(3.5%NaCl)at room temperature, using a potentiostat(model solartron SI 1287).Samples for corrosion testing were cleaned and rinsed in distilled water, and dried, Oh et al (2002). The potential scanning rate was 0.5mV/s, the scanning rang was -800mV_500mV, platinum auxiliary electrode, and a saturated calomel electrode (SCE) was used as the reference electrode.…”

Corrosion evaluation of orthodontic wires in artificial saliva solutions by using response surface methodology

“…Indeed, the anticorrosive behavior of Ni-Ti-based wires has been evaluated in several works 5,[7][8][9][10] , which presented different results, in the great majority of the cases. Kim and Johnson 7 analyzed the breakdown potential of stainless steel, Ni-Ti, and titanium orthodontic wires in 0.9% m/v NaCl.…”