Tooth whitening products containing hydrogen peroxide or carbamide peroxide were evaluated in this review for potential oral cancer risk from their use. Hydrogen peroxide is genotoxic in vitro, but not in vivo. Hydrogen peroxide was not considered to pose a genotoxic risk to humans. The animal toxicology data relevant to the assessment of the carcinogenicity of hydrogen peroxide do not indicate that it has significant carcinogenic activity at any site, including the oral cavity. Hydrogen peroxide was found to enhance the carcinogenic effects of potent DNA reactive carcinogens in experimental animals. However, these experimental conditions are artificial as they are related to high exposures and are of no relevance to potential human exposures to low quantities of hydrogen peroxide from the use of tooth whitening products. Clinical data on hydrogen peroxide-containing tooth whitening products show no evidence for the development of preneoplastic or neoplastic oral lesions. Exposures to hydrogen peroxide received by the oral cavity are exceedingly low, of short duration (30-60 minutes), and could not plausibly enhance any carcinogenic risk associated with exposure of the oral cavity to chemicals in cigarette smoke or to alcohol, both known risk factors for the development of oral cancer.
Clinical significance: Based on a comprehensive review of the available literature and research, the use of tooth whitening products containing hydrogen peroxide or carbamide peroxide does not appear to pose an increased risk of oral cancer in the general population, including those persons who are alcohol abusers and/or heavy cigarette smokers.