Evaluating of Nickel and Chromium Ions Release from Orthodontic Wires After Use of Teeth Whitening Mouthwashes

Background: Nickel (Ni) and chromium (Cr) ions are released from orthodontic wires due to corrosion, potentially causing allergic reactions and cytotoxic effects. Teeth-whitening mouthwashes contain active ingredients that may accelerate metal ion release. This study evaluates the release of Ni and Cr ions from orthodontic wires following exposure to different whitening mouthwashes. Materials and Methods: A total of 60 stainless steel orthodontic wires were immersed in three different whitening mouthwashes (Group A, B, and C) and artificial saliva (control) for 30 days. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to measure ion release at intervals of 7, 15, and 30 days. The pH and composition of the mouthwashes were analyzed to determine their corrosive potential. Results:Nickel and chromium ion release was significantly higher in all test groups compared to the control. Group A showed the highest Ni release (4.2 ± 0.3 µg/L), followed by Group B (3.5 ± 0.4 µg/L) and Group C (2.8 ± 0.2 µg/L), while the control had the lowest (1.2 ± 0.1 µg/L). Similarly, Cr release was highest in Group A (2.1 ± 0.2 µg/L), followed by Group B (1.8 ± 0.3 µg/L), and Group C (1.5 ± 0.2 µg/L), whereas the control exhibited the lowest release (0.7 ± 0.1 µg/L). A statistically significant increase in ion release was observed over time (p < 0.05). Conclusion: Whitening mouthwashes contribute to increased release of Ni and Cr ions from orthodontic wires, with variations depending on their composition and pH. Prolonged exposure may pose biocompatibility concerns, highlighting the need for patients undergoing orthodontic treatment to use whitening mouthwashes cautiously.