Genotoxicity and oral tissue damage associated with tooth bleaching agents: A scoping review

Tooth bleaching is one of the most frequently performed esthetic procedures in dentistry. Although peroxide-based bleaching agents effectively promote color change, their decomposition generates reactive oxygen species that may induce oxidative stress, cytotoxicity, genotoxicity, inflammation, and oral tissue alterations. This scoping review mapped and synthesized the available evidence regarding genotoxicity and oral tissue damage associated with tooth bleaching procedures, identified the biological models and analytical methods used to investigate these outcomes, and explored differences among bleaching protocols. The review followed the Joanna Briggs Institute methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines. Searches were conducted in major electronic databases and supplementary searches. Ninety-four studies were included, comprising laboratory, animal, and human investigations. The most commonly used analytical methods included micronucleus assays, comet assays, oxidative stress biomarkers, molecular analyses, and histopathological evaluations. Peroxide-based bleaching agents were frequently associated with oxidative stress, cytotoxicity, genotoxicity, inflammatory responses, apoptosis, and tissue alterations, which appeared to occur in a concentration-dependent and time-dependent manner. Laboratory studies generally reported more pronounced biological effects, whereas animal and clinical investigations demonstrated the influence of physiological defense and repair mechanisms. Clinical studies frequently reported transient biological alterations. Oxidative stress emerged as the central mechanism linking peroxide exposure to cellular and tissue damage. Overall, peroxide concentration, exposure duration, and protocol design emerged as relevant factors modulating biological responses, whereas catalysts, antioxidants, and photobiomodulation therapies represented promising strategies to mitigate bleaching-induced damage. Further standardized and long-term clinical studies are required to clarify the biological significance and clinical relevance of these effects.