title: Comparative effects of photodynamic therapy mediated by curcumin on standard and clinical isolate of Streptococcus mutans.
abstract: 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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
  
  
  
  Alternative antimicrobial approaches, as photodynamic therapy, should be encouraged due to optimal results against cariogenic bacteria aiming to prevent or treat dental caries.
authors: Araraquara Dental School, Universidade Estadual Paulista Araraquara, São Paulo, Brazil.
authors: Caroline C
authors: CC
authors: Tonon
authors: Master Program in Dentistry, CEUMA University, São Luís, Maranhão, Brazil.
authors: Marco Aurélio
authors: MA
authors: Paschoal
authors: Department of Pediatric Dentistry, Araraquara Dental School Universidade Estadual Paulista, Araraquara, São Paulo, Brazil.
authors: Marilia
authors: M
authors: Correia
authors: Department of Pathology and Physiology, Araraquara Dental School, Universidade Estadual Paulista, Araraquara, São Paulo, Brazil.
authors: Denise M P
authors: DM
authors: Spolidório
authors: São Carlos Institute of Physics, University of São Paulo, São Carlos, São Paulo, Brazil.
authors: Vanderlei S
authors: VS
authors: Bagnato
authors: São Carlos Institute of Physics, University of São Paulo, São Carlos, São Paulo, Brazil.
authors: Juçaíra S M
authors: JS
authors: Giusti
authors: PhD, Department of Pediatric Dentistry, Araraquara Dental School Universidade Estadual Paulista, Araraquara, São Paulo, Brazil, Rua Humaité, 1680 Araraquara, São Paulo 14801-903, Brazil Phone: 55 16 33016330, Fax: 55 16 33016328, e-mail: lspinto@foar.unesp.br.
authors: Lourdes
authors: L
authors: Santos-Pinto
mesh_terms: D058491:Bacterial Load / Q000187:drug effects; D001431:Bacteriological Techniques; D003474:Curcumin / Q000008:administration & dosage / Q000627:therapeutic use*; D003731:Dental Caries / Q000382:microbiology; D006801:Humans; D050296:Microbial Viability / Q000187:drug effects; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D011829:Radiation Dosage; D013295:Streptococcus mutans / Q000187:drug effects*
chemical_list: D017319:Photosensitizing Agents; D003474:Curcumin
keywords: Streptococcus mutans; Photochemotherapy; Curcumin.