Estudo in situ do efeito antimicrobiano da terapia fotodinâmica em lesões de cárie dentinária

Abstract

Photodynamic therapy is a concept of treatment, suggested by the literature as a potential therapy capable of inactivating microbial. Thus, this study assessed the efficacy of photodynamic therapy on injuries of dentine caries by a in situ design of single phase. During 14 days, 20 volunteers wore intra-oral palatal devices containing six human dental dentine slabs. The volunteers wore asked to drop a 40% sucrose solution onto the slabs ten times per day, in order to simulate a cariogenic challenge and to use fluoride dentifrice three times per day. At the end of the experimental period the slabs were randomly allocated into one of the following groups: without sensitizer and light (S-L-); with sensitizer and without light (S+L-); without sensitizer and irradiated with 47J/cm2 energy density (S-L+47); without sensitizer and irradiated with 94J/cm2 energy density (S-L+94); with sensitizer and irradiated with 47J/cm2 energy density (S+L+47); and with sensitizer and irradiated with 94J/cm2 energy density (S+L+94). The sensitizer of choice was the toluidine blue O at 100 g/mL concentration and radiation originated from a light-emitting diode (LED) with a 638,8 nm predominant wavelength. Before and after the treatments, dentine samples were collected and analyzed to figure out the total microorganisms, total streptococci, mutans streptococci and lactobacilli. The data of the counts were transformed into log10.The values of log reduction was achieved and the statistical differences identified by ANOVA One way and Tukey Kramer tests (p<0,05). In both analyses statistically significant difference between the microbial counts before and after treatment in groups (S-L+47), (S+L+94), (S+L+94) for all microorganisms tested are founded. It was concluded that PACT in the tested parameters was effective in promoting microbial death and that the exposure time of dentine to 10 minutes of light was also effective in microbial inactivation.