Antimicrobial photodynamic therapy on Streptococcus mutans is altered by glucose in the presence of methylene blue and red LED

Effect of Photodynamic Therapy on Microorganisms Responsible for Dental Caries: A Systematic Review and Meta-Analysis

“…The systematic review showed that among the cariogenic microorganisms listed in the selected studies, the most studied microorganism was Streptococcus mutans (82%) [12,14,15,16,17,18,19,20,21,23,24,25,26,27,28,29,31,32,33,34,35,37,39,40,41,42,43,45].…”

“…The success of PDT depends on factors such as the administrated dose of light in the target cells and the time of exposure to light [46]. Considering these factors, we found that the most widely used light source was the red LED (32%) with wavelengths ranging from 625 to 670 nm [12,15,16,17,18,21,24,29,30,32,36,40], the most commonly used PS was methylene blue [13,16,18,21,23,24,27,28,29,30,32,33,36,38,39,42], and the most widely used pre-irradiation time was 5 min [12,14,15,16,17,19,20,21,22,27,28,30,31,32,33,39,42,43,45].…”

“…For a substance to be considered as a bactericide, it is necessary for a total inhibition of microorganism growth or ≤99.9% decrease in the initial inoculum (3-log 10 reduction in colony forming units [cfu]/mL) in the subculture [68]. From the 34 articles analyzed, only 11 presented a reduction greater than or equal to 99.9% [14,16,18,23,24,29,34,39,41,43,45]. This fact proves that eliminating these microorganisms is a great challenge, especially when they are in the biofilm.…”

“…Among the vitro studies, the biofilm models were more frequent [12,13,15,18,19,20,21,24,27,28,31,32,33,34,35,37,38,39,40,43,44,45] than the suspensions, which confirm the fidelity of the data, since in biofilms, the microorganisms interact with each other and are more resistant to the antimicrobial agents when compared to the microorganisms in suspension [75]. Many studies have used monotypic biofilms of S. mutans , but this model is less representative of the oral environment and underestimates the complexity of the dental biofilm [76], so we emphasize the importance of studies with multispecies biofilms.…”

Photodynamic Effect of Methylene Blue and Low Level Laser Radiation in Head and Neck Squamous Cell Carcinoma Cell Lines

“…As light source a diode laser operating at 655 nm was used [ 21 ]. MB concentrations used in clinical studies ranged from 100 µg/mL [ 22 ] to 10 µg/mL [ 23 ].…”