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Abstract
A paradox in metabolism is that, while the majority of complex life on Earth requires oxygen for its existence, oxygen is a highly reactive molecule that damages living organisms by producing reactive oxygen species (ROS). Thus, organisms contain a complex network of antioxidant metabolites and enzymes that work together to prevent oxidative damage to cellular components such as DNA, lipids, and proteins. Maintaining a good balance of oxidants and antioxidants is important for oral and systemic health. Lots of factors can lead to a misbalance of oxidants in oral tissues, such as alcohol, nicotine, pollutants and general stress. It causes an oxidative stress and may damage or kill cells by overly reactive oxygencontaining molecules and chronic excessive inflammation.
Pernicious impacts of ROS are balanced by non-enzymatic and enzymatic antioxidants. Exhausted antioxidant defense mechanisms bringing to oxidative damage to normal tissues and cells, and the breakdown of the fragile balance between oxidants/antioxidants is a cause of carcinogenesis.
In this work, it will be reviewed the processes that lead to the oxidative/antioxidant imbalance, the role of preventing antioxidants and their sources, antioxidants as food additives. The importance of saliva will be highlighted, since it plays an important role in this process and it is a fluid where many biochemical processes are taking place - the process of mastication and digestion of ingested foods promotes a variety of reactions, including lipid peroxidation. It acts as a cleansing solution, an ion reservoir, a lubricant and a buffer. It could constitute a first line of defense against free radical-mediated oxidative stress.
