Influence of antimicrobial photodynamic therapy with different pre-irradiation times on children's dental biofilm: randomized clinical trial.

Abstract

Photodynamic therapy (PDT) is effective in reducing pathogenic microorganisms in the oral cavity and in preventing dental diseases. This study evaluated the pre-irradiation time using PDT (diode laser associated with 0.01% methylene blue) to decrease the number of microorganisms in the visible plaque in permanent teeth. This randomized clinical trial included 108 homologous lower permanent first molars (36 and 46) with biofilm from 54 children aged six to 12years. PDT was performed (0.01% methylene blue photosensitizer/therapeutic laser-InGaAIP), according to the following protocols: Group 1, biofilm collection of the distal area of the lingual surface of 36µm before PDT; group 2, mesial area of the lingual surface of 36µm 1min after PDT; group 3, area of the lingual surface of 46µm before PDT; and group 4, mesial area of the lingual surface of 46µm 5min after PDT. After statistical analysis, significant differences were observed between the groups (p = 0.000). In groups 2 and 4, the number of bacteria tended to decrease, with a more evident bacterial reduction in group 4. Pre-irradiation reduced the number of colony-forming units of mature bacterial biofilms in vivo. A time of 5min resulted in a greater reduction in the number of colony-forming units. ReBEC Identifier: RBR-6bqfp3; Date of Register: March 2nd, 2020. Retrospectively Registered.