Nickel accumulation in saliva and urine post orthodontic fixed appliance treatment in Malay population / Nadia Izyan Muhamad Sabri, Indah Yuri Noviaranny and Jamil Ahsan Kazi

Objective: Prolonged nickel exposure, even in low amounts, is cytotoxic, genotoxic and carcinogenic. The study aims to evaluate the salivary and urinary nickel levels post-orthodontic fixed appliance treatment.
Materials and Methods: Saliva and urine samples of fourteen orthodontic patients were taken at debonding (T0), after one month (T1), and three months post-debonding (T2), and compared with the control group. Samples were analysed using Inductively Coupled Plasma Optical Mass Spectrometry (ICP-MS) and IBM SPSS Version 27 was used for statistical analyses.
Results: The mean (SD) of orthodontic treatment duration was 33.6 (9.6) months. In comparison to the control group, the mean (SD) nickel levels in saliva and urine were highest at debonding (T0) with 12.71 ppb (9.64) and 9.71 ppb (8.27), respectively. In the test group, there was a significant difference in nickel level in saliva between T0 and T1 (MD = 9.75, 95% CI: 3.71, 15.71; p < 0.05) and in urine between T0 and T1 (MD = 6.46, 95% CI: 1.38, 11.55; p = 0.012).
Conclusion: Our results clearly demonstrated that the nickel level in saliva and urine remained higher at the end of orthodontic treatment compared to the control group. Further studies with a longer duration of observation and larger samples are suggested. Furthermore, our study indicates it is essential to confirm the effects of long-duration of orthodontic treatment and its post-treatment nickel level. This study raised attention about the biocompatibility of mechanical orthodontic treatment vs sustainable general health.