Galvanic corrosion of and ion release from various orthodontic brackets and wires in a fluoride-containing mouthwash

This study compared the galvanic corrosion of orthodontic wires and brackets from various manufacturers following exposure to a fluoride mouthwash. This study was conducted on 24 lower central incisor 0. 022” Roth brackets of four different commercially available brands (Dentaurum, American Orthodontics, ORJ, Shinye). These brackets along with stainless steel (SS) or nickel-titanium (NiTi) orthodontic wires (0. 016«, round) were immersed in Oral-B mouthwash containing 0. 05% sodium fluoride for 28 days. The electric potential (EP) difference of each bracket-wire couple was measured with a Saturated Calomel Reference Electrode (Ag/AgCl saturated with KCl) via a voltmeter. The ions released in the electrolyte were measured with an atomic absorption spectrometer. All the specimens were assessed under a stereomicroscope and specimens with corrosion were analyzed with scanning electron microscopy (SEM). Data were analyzed using ANOVA. The copper ions released from specimens with NiTi wire were greater than those of samples containing SS wire. ORJ brackets released more Cu ions than other samples. The Ni ions released from Shinye brackets were significantly more than those of other specimens (P < 0. 05). Corrosion rate of brackets coupled with NiTi wires was higher than that of brackets coupled with SS wires. Light and electron microscopic observations showed greater corrosion of ORJ brackets. In fluoride mouthwash, Shinye and ORJ brackets exhibited greater corrosion than Dentaurum and American Orthodontics brackets. Stainless steel brackets used with NiTi wires showed greater corrosion and thus caution is recommended when using them.