Determination of metal ions release from orthodontic archwires in artificial saliva using inductively coupled plasma-optical emission spectrometer (ICP-OES)

Over the last decades many concerns have been raised regarding the migration of potentially toxic metals from the orthodontic appliances to the oral environment due to the dynamic dominant conditions. The current study aimed to investigate the effect of the oral environment acidity and aging time on the ion release from orthodontic archwires. For this purpose, dental archwires consisted of three different alloys were immersed in artificial saliva of varied pH values for 7 and 30 days at 37±1°C. The liquid extracts were then analyzed with inductively coupled plasma-optical emission spectrometer (ICP-OES). It was found that the released ion species and the measured concentrations were not in accordance with manufacturers’ data. Furthermore, the leachates were mainly enriched with Cr and Ni ions by decreasing the saliva pH, while most of the archwires released the highest amounts of Ni, Mn and Cr ions after 30 days aging at pH = 3.5. Independent of the material type or the aging conditions, the total release of Ni and Cr ions was within the considered average dietary intake levels.