title: Photodynamic Inactivation of Cariogenic Pathogens Using Curcumin as Photosensitizer.
abstract: OBJECTIVE
  This investigation assessed the susceptibility of Streptococcus mutans and Lactobacillus acidophilus to Photodynamic Therapy (PDT) when grown simultaneously in dentine carious lesions.
  
  
  BACKGROUND
  PDT is a technique that utilizes light to activate photosensitizers in the presence of oxygen to produce reactive radicals.
  
  
  METHODS
  A culture medium of 1% glucose, 2% sucrose, 1% young primary culture of L. acidophilus 108CFU/mL, and S. mutans 108CFU/mL was utilized to inoculate the bacterial induced caries on human dentine slabs. Different concentrations of the photosensitizer (0.75, 1.5, 3.0, 4.0, and 5.0 g/L) were activated through exposure to the light-emitting diode source with a central wavelength of 450 nm and a fluency of 5.7 J/cm2. Two light intensities (19 and 47.5 mW/cm2) were tested. Four different groups were analyzed: L-D- (control group), L-D+ (drug group), L+D+1 (PDT group 1, light intensity of 19 mW/cm2), and L+D+2 (PDT group 2, light intensity of 47.5 mW/cm2). ANOVA/Tukey tests were utilized to compare groups (α = 5%).
  
  
  RESULTS
  Both light intensities required 5.0 g/L of curcumin for significant bacterial reduction (p < 0.05). No significant effect was found for L-D+, thus proving the absence of a potential inherent toxicity.
  
  
  CONCLUSIONS
  Curcumin has a toxic effect on microorganisms at appreciable concentrations upon photoactivation. However, it was required to use the maximum concentration of the drug for a successful procedure.
authors.affiliation: 1 Department of Restorative Dentistry, Dental School of Pernambuco, University of Pernambuco (UPE) , Camaragibe, Brazil .
authors.forename: Natália Costa
authors.initials: NC
authors.lastname: Araújo
authors.affiliation: 2 Department of Endodontics, University of Pernambuco (UPE) , Camaragibe, Brazil .|3 Center for Biophotonics, University of California , Davis (UCDavis), Sacramento, California.
authors.forename: Rebeca Ferraz
authors.initials: RF
authors.lastname: de Menezes
authors.affiliation: 1 Department of Restorative Dentistry, Dental School of Pernambuco, University of Pernambuco (UPE) , Camaragibe, Brazil .|7 Faculty of Dentistry, University Center Tabosa de Almeida ASCES-UNITA, Caruaru, Brazil .
authors.forename: Vanda Sanderana Macêdo
authors.initials: VSM
authors.lastname: Carneiro
authors.affiliation: 2 Department of Endodontics, University of Pernambuco (UPE) , Camaragibe, Brazil .
authors.forename: Alexandrino Pereira
authors.initials: AP
authors.lastname: Dos Santos-Neto
authors.affiliation: 4 Department of Clinical Analysis, School of Pharmaceutical Sciences , Universidade Estadual Paulista (UNESP), Araraquara, Brazil .
authors.forename: Carla Raquel
authors.initials: CR
authors.lastname: Fontana
authors.affiliation: 5 Optics Group from Physics Institute of São Carlos (IFSC), University of São Paulo (USP) , São Carlos, Brazil .
authors.forename: Vanderlei Salvador
authors.initials: VS
authors.lastname: Bagnato
authors.affiliation: 3 Center for Biophotonics, University of California , Davis (UCDavis), Sacramento, California.
authors.forename: Catherine Malinda
authors.initials: CM
authors.lastname: Harvey
authors.affiliation: 6 Laser Center, University of Pernambuco (UPE) , Camaragibe, Brazil .
authors.forename: Marleny Elizabeth Martinez
authors.initials: MEM
authors.lastname: Gerbi
mesh_terms: D000704:Analysis of Variance; D003474:Curcumin / Q000494:pharmacology*; D003731:Dental Caries / Q000188:drug therapy* / Q000382:microbiology; D006801:Humans; D066298:In Vitro Techniques; D007779:Lactobacillus acidophilus / Q000187:drug effects / Q000472:pathogenicity; D008826:Microbial Sensitivity Tests; D008963:Molar / Q000187:drug effects / Q000382:microbiology; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D013295:Streptococcus mutans / Q000187:drug effects / Q000472:pathogenicity
chemical_list: D017319:Photosensitizing Agents; D003474:Curcumin
keywords: dentin; dentistry; photodynamic therapy