The effectiveness of Vitamin C on the Level of Salivary Total Antioxidant Capacity (TAC) in bruxism patients with pain: a randomized clinical trial

Abstract

Introduction: Bruxism is a para-functional disorder and the prevalence of this rhythmic activity of masticator muscles is 8-31.4%. The exact pathophysiology of bruxism is still unclear. For this reason, traditional treatments such as splint bite are not always effective and can lead to complications such as increased pain during the patient’s rest. Based on the fact that the oxidative stress imbalance leads to tissue damage and is a life-threatening factor, and as it has recently been announced that there is an imbalance in the oxidative stress and reduction of antioxidants in people suffering from bruxism, in this research the effectiveness of Vitamin C was evaluated on the level of Salivary Total Antioxidant Capacity (TAC) in bruxism patients for diagnostic and treatment purposes.
Materials & Methods: Thirty patients with bruxism were selected for this double-blind, placebo-controlled study. The patients were randomly divided into two groups who used vitamin C 250 mg/day (n=15) and placebo (n=15) for one month. The measurement of TAC as well as the amount of pain based on the Numerical Rating Scale (NRS) was performed before the onset of drug therapy and at the end of the first month. The statistical analysis was performed using ANOVA test and Repeated Measure ANOVA. 
Results: Based on the observations, there was no significant difference between the TAC of stimulated (p=0.12) and un-stimulated (P=0.13) saliva as well as pain (p=0.48) after intervention between the two considered groups (group receiving vitamin C and group receiving placebo in bruxism patients). The results obtained from pre- and post-intervention indicated that TAC of un-stimulated saliva (P=0.73) and pain (P=0.94) decreased in both groups, though it was not statistically significant. On the other hand, the TAC of stimulated saliva (p=0.60) increased in the intervention group and decreased in the control group but again it was not statistically significant in both groups. No significant side effects were observed in the two groups.
Conclusion: Based on this study, we found that vitamin C (250 mg/day) enhanced the total antioxidant capacity (TAC) of stimulated saliva. However, statistically it did not make any significant changes in stimulated and un-stimulated saliva in patients with bruxism. Further, it reduced pain in these patients which was not statistically significant either. Numerous studies have demonstrated that oxidant and antioxidant imbalance is associated with bruxism. Nevertheless, so far it has not been determined whether oxidative imbalance leads to bruxism or‌ vice versa. Therefore, it can be concluded from this study that oxidant imbalance in the pathogenesis of bruxism does not play a significant role and perhaps patients suffer from decreased antioxidant capacity after bruxism. In this case, vitamin C or other antioxidant supplements are advised to prevent harmful effects of diminished body’s antioxidant capacity. Still, it is recommended to perform studies with a longer follow-up and larger sample size and higher dose of vitamin C, even in combination with other antioxidant supplements, in order to obtain more reliable results.