AIM:The aim of this study was investigate the effect of photodynamic therapy (PDT) using curcumin (C) as a photosensitizing agent irradiated with an LED (L) in the blue wavelength as a light source on a standard and clinical isolate of Streptococcus mutans (S. mutans) in a planktonic suspension model.

MATERIALS AND METHODS:Suspensions of both strains were divided into 4 groups as follows: absence of C and L (control group: C-L-), with C and without L (C group: C+L-), absence of C with L (L group: C-L+) and presence of C and L (PDT group: C+L+). Three different concentrations of curcumin (0.75 mg/ml, 1.5 mg/ml and 3 mg/ml) and three light fluences of studied light source (24, 48 and 72 J cm(-2)) were tested. Aliquots of each studied group was plated in BHI agar and submitted to colony forming units counting (CFU/ml) and the data transformed into logarithmical scale.

RESULTS:A high photoinactivation rate of more than 70% was verified to standard S. mutans strain submitted to PDT whereas the clinical isolate showed a lower sensitivity to all the associations of curcumin and LED. A slight bacterial reduction was verified to C+L- and C-L+, demonstrating no toxic effects to the isolated application of light and photosensitizer to both S. mutans strains tested.

CONCLUSION:Photodynamic therapy using a combination of curcumin and blue LED presented a substantial antimicrobial effect on S. mutans standard strain in a planktonic suspension model with a less pronounced effect on its clinical isolate counterparts due to resistance to this alternative approach.

CLINICAL SIGNIFICANCE:Alternative antimicrobial approaches, as photodynamic therapy, should be encouraged due to optimal results against cariogenic bacteria aiming to prevent or treat dental caries.

AIM:The aim of this study was investigate the effect of photodynamic therapy (PDT) using curcumin (C) as a photosensitizing agent irradiated with an LED (L) in the blue wavelength as a light source on a standard and clinical isolate of Streptococcus mutans (S. mutans) in a planktonic suspension model.

MATERIALS AND METHODS:Suspensions of both strains were divided into 4 groups as follows: absence of C and L (control group: C-L-), with C and without L (C group: C+L-), absence of C with L (L group: C-L+) and presence of C and L (PDT group: C+L+). Three different concentrations of curcumin (0.75 mg/ml, 1.5 mg/ml and 3 mg/ml) and three light fluences of studied light source (24, 48 and 72 J cm(-2)) were tested. Aliquots of each studied group was plated in BHI agar and submitted to colony forming units counting (CFU/ml) and the data transformed into logarithmical scale.

RESULTS:A high photoinactivation rate of more than 70% was verified to standard S. mutans strain submitted to PDT whereas the clinical isolate showed a lower sensitivity to all the associations of curcumin and LED. A slight bacterial reduction was verified to C+L- and C-L+, demonstrating no toxic effects to the isolated application of light and photosensitizer to both S. mutans strains tested.

CONCLUSION:Photodynamic therapy using a combination of curcumin and blue LED presented a substantial antimicrobial effect on S. mutans standard strain in a planktonic suspension model with a less pronounced effect on its clinical isolate counterparts due to resistance to this alternative approach.

CLINICAL SIGNIFICANCE:Alternative antimicrobial approaches, as photodynamic therapy, should be encouraged due to optimal results against cariogenic bacteria aiming to prevent or treat dental caries.

To investigate effects of light wavelengths and coherence on growth of liquid-cultured Inonotus obliquus mycelia, melanin accumulation and enzymes activity, culture condition as light of different wavelengths and coherence were studied. Short-term exposure of the vegetative mycelium by low-intensity coherent blue light was optimal for stimulation of growth, melanin synthesis, and increase in extracellular and intracellular activities of tyrosinase and polyphenoloxidase and extracellular catalase. Red coherent light, in the same mode, can effectively be used to stimulate the growth of mycelium and to increase intracellular and extracellular activity of polyphenoloxidase, extracellular catalase and tyrosinase, and intracellular peroxidase. Low-coherent light had less stimulating effect on the biosynthetic activity of I.оbliquus. It should be used in the cultivation directed at the obtaining endomelanin, polyphenoloxidase, and extracellular tyrosinase.