Orthodontic stainless steel wire and nickel release

The release of nickel was not necessarily proportional to the alloy's nickel content. Stainless steel has 8% in his content, however, this biocompatibility may be altered with possible differences in salivary pH and presence of fluoride. The analysis of the corrosion products was carried out for the nickel ion using the spectrophotometers GBC 932 Scientific Equipment PTY, model 932 and Unican, model 939 for each sample as a function of pH (4 and 6,75)/time/ppm fluoride ion (1500 and 22600 ppm). The condition with the longest immersion time at pH 4 was the only one that presented an outcome for the Ni ion above the sensitivity limit of the technique Considering the drawbacks of this in vitro study the results lead to conclude that lowering pH and increasing the immersion time are the most corrosive conditions.