title: Effect of low-level GaAlAs laser irradiation on the proliferation rate of human periodontal ligament fibroblasts: an in vitro study.
abstract: OBJECTIVE
  The aim of this in vitro study was to evaluate a potential stimulatory effect of low-level laser irradiation on the proliferation of human periodontal ligament fibroblasts (PDLF).
  
  
  METHODS
  PDLF obtained from third molar periodontal ligaments were cultured under standard conditions and spread on 96-well tissue culture plates. Subconfluent monolayers were irradiated with an 809-nm diode laser operated at a power output of 10 mW in the continuous wave (cw) mode at energy fluences of 1.96-7.84 Jcm-2. The variable irradiation parameters were the time of exposure (75-300 s per well) and the number of irradiations (1-3). After laser treatment, the cultures were incubated for 24 h. The proliferation rate of the lased and control cultures was determined by means of fluorescence activity of a reduction-oxidation (REDOX) indicator (Alamar Blue Assay) added to the cell culture. Proliferation, expressed in relative fluorescence units (RFU), was determined 24, 48 and 72 h after irradiation.
  
  
  RESULTS
  The irradiated cells revealed a considerably higher proliferation activity than the controls. The differences were significant up to 72 h after irradiation (Mann-Whitney U-test, p<0.05).
  
  
  CONCLUSIONS
  A cellular effect of the soft laser application is clearly discernible. Clinical studies are needed to evaluate whether the application of low-level laser therapy might be beneficial in regenerative periodontal therapy.
authors.affiliation: Department of Oral Surgery, Johannes Gutenberg-University, Augustusplatz 2, 55131 Mainz, Germany. matthiaskreisler@web.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Kreisler
authors.forename: Ann B
authors.initials: AB
authors.lastname: Christoffers
authors.forename: Britta
authors.initials: B
authors.lastname: Willershausen
authors.forename: Bernd
authors.initials: B
authors.lastname: d'Hoedt
mesh_terms: D000535:Aluminum; D001151:Arsenic; D002455:Cell Division / Q000528:radiation effects; D002478:Cells, Cultured; D004396:Coloring Agents; D005347:Fibroblasts / Q000528:radiation effects*; D005453:Fluorescence; D005708:Gallium; D006801:Humans; D007202:Indicators and Reagents; D007834:Lasers; D010078:Oxazines; D010513:Periodontal Ligament / Q000166:cytology / Q000528:radiation effects*; D011829:Radiation Dosage; D018709:Statistics, Nonparametric; D013997:Time Factors; D014966:Xanthenes
chemical_list: D004396:Coloring Agents; D007202:Indicators and Reagents; D010078:Oxazines; D014966:Xanthenes; C005843:resazurin; D005708:Gallium; D000535:Aluminum; D001151:Arsenic