eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2015-10-25 8 October Spl Edition 453 460 10.13005/bpj/722 4316 article T. Manigandan 1 Sarumathi 1 A. Amudhan 1 Sree Balaji Dental College and Hospital, Bharath University, Chennai, India Free radical is a molecule or molecular fragment containing an unpaired electron in the valence shell (i.e. radical) and capable of existing independently (i.e. free)¹. They are unstable, short lived and highly reactive. Oxidative stress is increased and antioxidant defences are compromised in patients with oral cavity cancer. Free radical has a definitive role in cacinogenesis which can also serve as a Potential biomarker for measuring oxidative stress levels in saliva and serum of patients affected with oral cancer and in preventing the possibilities of turning of potentially pre-malignant disorders into malignant disorders. It is necessary to maintain a balance between free radicals and antioxidant defensive mechanism, to prevent the outbreak of Oral Cancer.   https://biomedpharmajournal.org/vol8octoberspledition/role-of-free-radicals-in-oral-carcinogenesis-a-review/ Free radical oral cancer Carcinogenesis biomarker reactive oxygen species reactive nitrogen species