Comparison of nickel and chromium ions released from stainless steel and NiTi wires after immersion in Oral B(R), Orthokin(R) and artificial saliva.

AIM: Oral environment of the mouth is a suitable place for biodegradation of alloys used in orthodontic wires. The toxicity of these alloys namely nickel and chromium has concerned the researchers about the release of these ions from orthodontic wires and brackets. The aim of this study was to measure the levels of nickel and chromium ions released from 0.018" stainless steel (SS) and NiTi wires after immersion in three solutions. MATERIALS AND METHODS: One hundred and forty-four round NiTi and 144 round SS archwires with the diameters of 0.018" were immersed in Oral B(R), Orthokin(R) and artificial saliva. The amounts of nickel and chromium ions released were measured after 1, 6, 24 hours and 7 days. RESULTS: Two way repeated ANOVA showed that the amount of chromium and nickel significantly increased in all solutions during all time intervals (p < 0.002). CONCLUSION: Chromium and nickel ions were released more in NiTi wire in all solutions compared with SS wire. The lowest increase rate was also seen in artificial saliva. CLINICAL SIGNIFICANCE: There is general consensus in literature that even very little amounts of nickel and chromium are dangerous for human body specially when absorbed orally; therefore, knowing the precise amount of these ions released from different wires when immersed in different mouthwashes is of high priority.