Background. The aim of this study is to determine the effect of fixed orthodontic appliance on the amount of vitamin C changes in patients undergoing orthodontic treatment referred to the Orthodontic Department of Islamic Azad University, and a private orthodontic clinic in Tehran (2017-18).

Method and materials. The study was performed using experimental method. The samples were collected randomly from a series of 30 patients. These specimens were collected at 3 different time intervals: before, one month later and three months after bonding by the residents of the orthodontic department and an orthodontist in a private clinic. The samples were analyzed by absorption spectrophotometry method and the changes in vitamin C were analyzed by ANOVA.

Results. The level of vitamin C in the above three mentioned different intervals was not statistically significant; although, the average rate has dropped during intervals using Kruskal-Wallis test. The level of vitamin C in some cases boosted in some cases remained unchanged and had an overall decrease due to the coefficient variation (over 100) and high standard deviation in the second and third intervals, which was more than 2.4 times of the mean, meanwhile age and sex did not have much or any impact on these changes (P = 0.4).

Conclusion. It seems that the use of fixed orthodontic devices does not affect the amount of vitamin C in saliva.

fixed orthodontic treatment, vitamin C, antioxidant, saliva.