Impact of Fluoride Mouthwash on Nickel ion Release from Orthodontic Brackets: An in-vitro Study

Introduction: In Orthodontic patients, the orthodontic brackets and wires are exposed to the oral fluids for a considerable period of time. Patients use fluoridated mouthwashes to maintain oral hygiene and avoid white spot lesions on their teeth, which can cause release of nickel and chromium from the orthodontic brackets and thus may lead to allergic reactions and cytotoxicity. Aim: To evaluate the amount of nickel ion release from orthodontic brackets on exposure to different fluoride mouthwash. Materials and Methods: This in-vitro experimental study was conducted on seventy-five Orthodontic brackets which were divided into three groups of 25 each and immersed in artificial saliva (group A), Amflor mouthwash (group B) and Zero sense (group C) mouthwash respectively in separate beakers. The temperatures of the solutions in the beakers were maintained at 37 degrees to simulate oral temperatures. The 5 mL of the solutions were drawn from the three breakers at 1 hour, 6 hours, 12 hours and 24 hours respectively and the Nickel ion release from each solution was measured using Optima 5300 Dual View (DV) Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). One-way Analysis of Variance (ANOVA) with a post hoc test was performed for comparison between the groups and at different time intervals. Results: The highest mean value of nickel release was noted in group C (0.32 +/- 0.020156 mu g/mL) at the 24 hrs peak time followed by group B (0.24 +/- 0.014338 mu g/mL). Statistical analysis showed a significant difference between the two experimental groups at all time periods except 1 hour (p-value <0.05). Conclusion: The amount of nickel ion release did not exceed the permissible limit in any of the study groups. However, it can be inferred that Amflor mouthwash can be prefered over Zero sense mouthwash for Orthodontic patients considering the lower nickel ion release.