Debridement of Bacterial Biofilms with TiO 2 /H 2 O 2 Solutions and Visible Light Irradiation.

Objectives: The aim of the study was to explore the debridement efficacy of different solutions of H2 O2 and rutile particles against Staphylococcus epidermidis and Pseudomonas aeruginosa biofilms attached to titanium surfaces when exposed to visible light.

Materials and Methods: Titanium discs cultivated with biofilms of Staphylococcus epidermidis or Pseudomonas aeruginosa were subjected for 1 min to suspensions consisting of rutile particles mixed with high (950 mM) or low (2 mM) concentrations of H2 O2 under visible light irradiation (405 nm; 2.1 mW/cm2 ). Discs were rinsed and the degree of debridement was determined through scanning electron microscopy and viability assessment of the remaining bacteria using luminescence measurements and/or a metabolic activity assay.

Results: Cleaning mixtures containing the higher concentration of H2 O2 showed a significantly improved debridement compared to the negative control in all experiments. The addition of rutile particles was shown to have a statistically significant effect in one test with S. epidermidis . Limited evidence of the catalytic effect of visible light irradiation was seen, but effects were relatively small and statistically insignificant.

Conclusions: H2 O2 at a concentration of 950 mM proved to be the strongest contribution to the debridement and bactericidal effect of the cleaning techniques tested in this study.