Application of hydrogen peroxide photolysis for reduction of cariogenic biofilm activity

Abstract

Dental caries is a multifactorial disease, and cariogenic biofilms play a crucial role in lesion development. Therefore, managing cariogenic biofilms is essential, and the development of novel and effective antimicrobial methods to reduce biofilm activity is desirable for caries management. Hydrogen peroxide (H₂O₂) photolysis generates hydroxyl radicals, which kill bacteria through oxidative activity. Since previous studies have suggested the potential application of H₂O₂ photolysis in caries management, this series of studies aimed to broaden knowledge about its effectiveness as a new caries management method. In Studies I, II, and III (in vitro experiments), H₂O₂ photolysis demonstrated strong antimicrobial effect against S. mutans biofilms and an inhibitory effect on tooth demineralization, using various samples, including hydroxyapatite discs, extracted rat teeth, and bovine dentin. Moreover, the antimicrobial activity of H₂O₂ photolysis was found to be greater than that of conventional antiseptics and antimicrobial photodynamic therapy. Study IV (an ex vivo experiment) revealed that H₂O₂ photolysis exerted antimicrobial effects against in vivo dental biofilms collected from volunteers identified as at increasing risk of dental caries. In addition, the technique did not affect the level of biofilm regrowth or its bacterial composition after treatment. These findings across all four studies suggest that this technique reduces biofilm activity regardless of its composition. In conclusion, this series of studies expands understanding of the potential of H₂O₂ photolysis as a new caries management strategy, highlighting its antimicrobial properties.