title: Transdentinal cell photobiomodulation using different wavelengths.
abstract: OBJECTIVE
  The aim of this study was to investigate the effects of transdentinal irradiation with different light-emitting diode (LED) parameters on odontoblast-like cells (MDPC-23).
  
  
  METHODS
  Human dentin discs (0.2 mm thick) were obtained, and cells were seeded on their pulp surfaces with complete culture medium (Dulbecco modified Eagle medium). Discs were irradiated from the occlusal surfaces with LED at different wavelengths (450, 630, and 840 nm) and energy densities (0, 4, and 25 J/cm(2)). Cell viability (methyltetrazolium assay), alkaline phosphatase activity (ALP), total protein synthesis (TP), and cell morphology (scanning electron microscopy) were evaluated. Gene expression of collagen type I (Col-I) was analyzed by quantitative polymerase chain reaction (PCR). Data were analyzed by the Mann-Whitney test with a 5% significance level.
  
  
  RESULTS
  Higher cell viability (21.8%) occurred when the cells were irradiated with 630 nm LED at 25 J/cm(2). Concerning TP, no statistically significant difference was observed between irradiated and control groups. A significant increase in ALP activity was observed for all tested LED parameters, except for 450 nm at 4 J/cm(2). Quantitative PCR showed a higher expression of Col-I by the cells subjected to infrared LED irradiation at 4 J/cm(2). More attached cells were observed on dentin discs subjected to irradiation at 25 J/cm(2) than at 4 J/cm(2).
  
  
  CONCLUSIONS
  The infrared LED irradiation at an energy density of 4 J/cm(2) and red LED at an energy density of 25 J/cm(2) were the most effective parameters for transdentinal photobiomodulation of cultured odontoblast-like cells.
authors.forename: A P S
authors.initials: AP
authors.lastname: Turrioni
authors.forename: F G
authors.initials: FG
authors.lastname: Basso
authors.forename: J R L
authors.initials: JR
authors.lastname: Alonso
authors.forename: C F
authors.initials: CF
authors.lastname: de Oliveira
authors.forename: J
authors.initials: J
authors.lastname: Hebling
authors.forename: V S
authors.initials: VS
authors.lastname: Bagnato
authors.forename: C A
authors.initials: CA
authors.lastname: de Souza Costa
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D003094:Collagen / Q000378:metabolism; D003804:Dentin / Q000166:cytology / Q000528:radiation effects*; D006801:Humans; D008027:Light; D008855:Microscopy, Electron, Scanning; D009804:Odontoblasts / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D010789:Phototherapy / Q000379:methods*; D016133:Polymerase Chain Reaction
chemical_list: D003094:Collagen; D000469:Alkaline Phosphatase