title: The impact of photodynamic therapy on the viability of Streptococcus mutans in a planktonic culture.
abstract: OBJECTIVE
  This study investigated the effect of photodynamic therapy (PDT) with toluidine blue O (TBO) and a light-emitting diode (LED) on the viability of Streptococcus mutans cells in a planktonic culture.
  
  
  BACKGROUND
  Growth of Streptococcus mutans is the first step in the development of tooth decay. The use of light and dyes promotes cellular death in a noninvasive way, reducing treatment time.
  
  
  METHODS
  The LED used in this study had output power of 116 mW, its energy was 21 J, and the fluency was 2.18 J/cm(2). Samples were prepared and divided into five groups: (1) control group (-); (2) control group (+); (3) TBO; (4) LED; and (5) LED + TBO.
  
  
  RESULTS
  One hundred percent of the bacteria were killed following irradiation with LED and TBO. The biofilm that formed on the glass surfaces was analyzed by SEM and colony count.
  
  
  CONCLUSIONS
  It was demonstrated that PDT was efficient at killing microorganisms and preventing the formation of biofilms.
authors.affiliation: Health and Sciences College, Vale do Paraíba University (UNIVAP), Urbanova, São José dos Campos, Brazil. isabevilacqua@terra.com.br
authors.forename: I M
authors.initials: IM
authors.lastname: Bevilacqua
authors.forename: R A
authors.initials: RA
authors.lastname: Nicolau
authors.forename: S
authors.initials: S
authors.lastname: Khouri
authors.forename: A
authors.initials: A
authors.lastname: Brugnera
authors.forename: G R
authors.initials: GR
authors.lastname: Teodoro
authors.forename: R A
authors.initials: RA
authors.lastname: Zângaro
authors.forename: M T T
authors.initials: MT
authors.lastname: Pacheco
mesh_terms: D018441:Biofilms / Q000254:growth & development / Q000528:radiation effects*; D002470:Cell Survival / Q000528:radiation effects; D004396:Coloring Agents; D054023:Lasers, Semiconductor; D008855:Microscopy, Electron, Scanning; D010778:Photochemotherapy; D010789:Phototherapy / Q000379:methods*; D013295:Streptococcus mutans / Q000502:physiology / Q000528:radiation effects*; D014048:Tolonium Chloride
chemical_list: D004396:Coloring Agents; D014048:Tolonium Chloride