Determination of the diffusion coefficient of methylene blue solutions in the dentin of a human tooth using reflection spectroscopy and their antibacterial activity by laser exposure

The work is devoted to the determination of the diffusion coefficients of methylene blue in pure aqueous solution and in a micellar solution of a cationic surfactant in human tooth dentinal sections in vitro using diffuse reflectance optical spectroscopy and the free diffusion model. The determination of the diffusion coefficient of methylene blue for an aqueous solution is (6.74 $\pm$ 1.32) $\times$ 10$^{-6}$ сm$^{2}$/s и (1.93 $\pm$ 0.24) $\times$ 10$^{-6}$ сm$^{2}$/s for methylene blue in micellar solution. Studies of toxicity in daylight in the absence of laser radiation of methylene blue solutions in water and in solution of cetylpyridinium chloride, as well as the photodynamic effect of laser radiation (662 nm) on cells of Candida albicans, Staphylococcus aureus FDA 209P and Lactobacillus were carried out. The effect of laser radiation has a pronounced suppressive effect on all the studied microbial strains.