Photodynamic effects of curcumin against cariogenic pathogens.
BACKGROUND
The presence of Streptococcus mutans and Lactobacillus acidophilus in dental structure is an indicator of a cariogenic biofilm. Photodynamic therapy is a technique that involves the activation of photosensitizers by light in the presence of oxygen, resulting in the production of reactive radicals capable of inducing cell death. Reduction of bacteria levels can provide additional means of preventing dental caries.


OBJECTIVE
The present study evaluated the susceptibility of planktonic cultures of S. mutans (ATCC 25175) and L. acidophilus (ATCC-IAL-523) from the Adolfo Lutz Institute (IAL) to photodynamic therapy after sensitization with curcumin and exposure to blue light at 450 nm.


METHODS
Bacterial suspensions of S. mutans and L. acidophilus isolated (as single species) and combined (multspecies) were prepared and then evaluated. Four different groups were analyzed: L-D- (control group), L-D+ (drug group), L+D- (light group), and L+D+ (photodynamic therapy group). Two different concentrations of curcumin were tested (0.75 and 1.5 g/L) associated with a 5.7 J/cm(2) light emission diode.


RESULTS
Significant decreases (p<0.05) in the viability of S. mutans were only observed when the bacterial suspensions were exposed to both curcumin and light. Then, reductions in viability of up to 99.99% were observed when using 1.5 g/L of the photosensitizer. The susceptibility of L. acidophilus was considerably lower (21% and 37.6%) for both curcumin concentrations.


CONCLUSIONS
Photodynamic therapy was found to be effective in reducing S. mutans and L. acidophilus on planktonic cultures. No significant reduction was found for L-D+, proving the absence of dark toxicity of the drug.
Dental School of Pernambuco, University of Pernambuco, Camaragibe, Brazil. nataliacosta84@yahoo.com.br
Natália Costa
NC
Araújo
Carla Raquel
CR
Fontana
Vanderlei Salvador
VS
Bagnato
Marleny Elizabeth Martinez
ME
Gerbi
D003474:Curcumin / Q000494:pharmacology*; D003731:Dental Caries / Q000382:microbiology*; D006801:Humans; D066298:In Vitro Techniques; D007779:Lactobacillus acidophilus / Q000187:drug effects*; D010778:Photochemotherapy; D013295:Streptococcus mutans / Q000187:drug effects*
D003474:Curcumin