Evaluation of determinants for the nickel release by the standard orthodontic brackets.

AIM

The study was aimed to assess the effect of different pH and immersion time on the amount of nickel release from simulated orthodontic appliance of 3M Unitek company.

MATERIAL AND METHOD

Nickel ion release was evaluated after subjecting the brackets to the simulated artificial oral environment. In this study, 90 stainless steel brackets of 3M Unitek Company were tested by immersing them in artificial saliva of pH 4.2, pH 6.5 and pH 7.6 for a time interval of 1hour, 1 week and 1 month (T1 - 1h, T2 - 7 days, T3 - 30 days) respectively. The data was subjected for the one-way ANOVA and the post-hoc test for the statistical comparison.

RESULTS

Means of 2.99±0.77, 9.53±4.26 and 12.65±2 .52 ppb (parts per billion by volume) of nickel were released for 4.2 pH at a time interval of 1hour, 7 days and 1 month respectively. Means of 5.37±2.26, 10.94±1.51 and 16.92±1.69 ppb of nickel were released for 6.5 pH at a time interval of 1hour, 7 days and 1 month respectively. A mean of 2.13±0.92, 0.74±0.54 and 18.83±1.02 ppb of nickel was released for 7.6 pH at a time interval of 1 hr, 7 days and 1 month respectively.

CONCLUSION

pH of the artificial saliva significantly affected the amount of nickel release. Acidic pH was found to increase the amount of nickel release in the artificial saliva. Time duration of bracket immersion significantly affected the amount of nickel release.