RESUMEN
There is significant evidence linking chronic periodontitis (CP) and oxidative stress (OS). CP is a multifactorial infecto-inflammatory disease caused by the interaction of microbial agents present in the biofilm associated with host susceptibility and environmental factors. OS is a condition that arises when there is an imbalance between the levels of free radicals (FR) and its antioxidant defences. Antioxidants, defined as substances that are able to delay or prevent the oxidation of a substrate, exist in all bodily tissues and fluids, and their function is to protect against FR. This systematic review assessed the effects of the complimentary use of antioxidant agents to periodontal therapy in terms of oxidative stress/antioxidants. Only randomised, controlled, double-blind or blind studies were included. The majority of the included studies were performed in chronic periodontitis patients. Lycopene, vitamin C, vitamin E, capsules with fruits/vegetables/berry and dietary interventions were the antioxidant approaches employed. Only the studies that used lycopene and vitamin E demonstrated statistically significant improvement when compared to a control group in terms of periodontal parameters. However, oxidative stress outcomes did not follow the same pattern throughout the studies. It may be concluded that the use of some antioxidants has the potential to improve periodontal clinical parameters. The role of antioxidant/oxidative stress parameters needs further investigations.