title: Comparative evaluation of photodynamic therapy using LASER or light emitting diode on cariogenic bacteria: An in vitro study.
abstract: OBJECTIVE
  The aim of this study was to evaluate in vitro the effect of photodynamic therapy (PDT) using LASER or light emitting diode (LED) on cariogenic bacteria (Streptococcus mutans [SM] and Lactobacillus casei [LC]) in bovine dentin.
  
  
  METHODS
  Twenty five fragments of dentin were contaminated with SM and LC strands and divided into five experimental groups according to the therapy they received (n = 5): C - control (no treatment), SCLED - no dye/LED application (94 J/cm(2)), SCLASER - no dye/LASER application (94 J/cm(2)), CCLED - dye/LED application (94 J/cm(2)) and CCLASER - dye/LASER application (94 J/cm(2)). The dye used was methylene blue at 10 mM. Dentin scrapes were harvested from each fragment and prepared for counts of colony forming units (CFU)/mL. The data were analyzed using Kruskal-Wallis, followed by Student-Newman-Keuls (α =0.05).
  
  
  RESULTS
  Regarding SM, groups CCLASER and CCLED showed a significant reduction in CFU/mL, which was statistically superior to the SCLASER, SCLED and C groups. Regarding LC, the groups CCLASER and CCLED caused a significant reduction in CFU/mL when compared with SCLASER, which showed intermediate values. SCLED and C had a lesser effect on reducing CFU/mL, where the former showed values similar to those of SCLASER.
  
  
  CONCLUSIONS
  In conclusion, PDT combined with LASER or LED and methylene blue had a significant antimicrobial effect on cariogenic bacteria in the dentin.
authors.affiliation: Department of Restorative Dentistry, São Leopoldo Mandic Institute and Research Center, Campinas, São Paulo, Brazil.
authors.forename: Liliana Guimarães Oliveira
authors.initials: LGO
authors.lastname: Ricatto
authors.affiliation: Department of Biomedical Engineering, Unicastelo, São José dos Campos, São Paulo, Brazil.
authors.forename: Luis Augusto Lopato
authors.initials: LAL
authors.lastname: Conrado
authors.affiliation: Department of Restorative Dentistry, São Leopoldo Mandic Institute and Research Center, Campinas, São Paulo, Brazil.
authors.forename: Cecilia Pedroso
authors.initials: CP
authors.lastname: Turssi
authors.affiliation: Department of Restorative Dentistry, São Leopoldo Mandic Institute and Research Center, Campinas, São Paulo, Brazil.
authors.forename: Fabiana Mantovani Gomes
authors.initials: FMG
authors.lastname: França
authors.affiliation: Department of Restorative Dentistry, São Leopoldo Mandic Institute and Research Center, Campinas, São Paulo, Brazil.
authors.forename: Roberta Tarkany
authors.initials: RT
authors.lastname: Basting
authors.affiliation: Department of Restorative Dentistry, São Leopoldo Mandic Institute and Research Center, Campinas, São Paulo, Brazil.
authors.forename: Flávia Lucisano Botelho
authors.initials: FLB
authors.lastname: Amaral
keywords: Lactobacillus casei; Streptococcus mutans; photodynamic therapy; semi-conductor lasers