title: Effects of low-level laser therapy on stem cells from human exfoliated deciduous teeth.
abstract: OBJECTIVE
  This study aimed to evaluate the influence of different laser therapy energy densities on SHED viability and proliferation.
  
  
  METHODS
  SHED were irradiated according to the groups: I (1.2 J/cm2 - 0.5 mW - 10 s), II (2.5 J/cm2 - 10 mW - 10 s), III (3.7 J/cm2 - 15 mW - 10 s), IV (5.0 J/cm2 - 20 mW - 10 s), V (6.2 J/cm2 - 25 mW - 10 s), and VI (not irradiated - control group). Cell viability was assessed 6 and 24 h after irradiation measuring the mitochondrial activity and using the Crystal Violet assay. Cell proliferation was assessed after 24, 48, and 72 h of irradiation by SRB assay.
  
  
  RESULTS
  MTT assay demonstrated differences from 6 to 24 hours after irradiation. After 24 h, groups I and IV showed higher absorbance values than those of control group. Crystal Violet assay showed statistically differences in the absorbance rate from 6 to 24 h after irradiation for groups III and VI. At 24 h after irradiation, Group III absorbance rate was greater than that of groups I, II, and IV. Group VI absorbance rate was greater than that of groups I and IV. SRB assay showed that the group I had higher rates than those of groups II, III, V, and VI, at 24 h after irradiation. After 48 h, group I exhibited the greatest cell proliferation rate followed by groups III, V, and VI. After 72 h, group III exhibited the lowest cell proliferation rate than those of groups II, IV, and V.
  
  
  CONCLUSIONS
  The Low-Level Laser Therapy energy densities used in this study did not cause loss of cell viability and stimulated SHED proliferation within the parameters described in this study.
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Odontopediatria, Ortodontia e Saúde Coletiva, Bauru, SP, Brasil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Fernandes
authors.affiliation: - Universidade Federal de Alfenas, Departamento de Clínica e Cirurgia, Alfenas, MG, Brasil.
authors.forename: Marina de Azevedo
authors.initials: Mde A
authors.lastname: Junqueira
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Odontopediatria, Ortodontia e Saúde Coletiva, Bauru, SP, Brasil.
authors.forename: Nádia Carolina Teixeira
authors.initials: NC
authors.lastname: Marques
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Odontopediatria, Ortodontia e Saúde Coletiva, Bauru, SP, Brasil.
authors.forename: Maria Aparecida Andrade Moreira
authors.initials: MA
authors.lastname: Machado
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Ciências Biológicas, Bauru, SP, Brasil.
authors.forename: Carlos Ferreira
authors.initials: CF
authors.lastname: Santos
authors.affiliation: - Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Odontopediatria, Ortodontia e Saúde Coletiva, Bauru, SP, Brasil.
authors.forename: Thais Marchini
authors.initials: TM
authors.lastname: Oliveira
authors.affiliation: - Universidade Federal de Alfenas, Departamento de Clínica e Cirurgia, Alfenas, MG, Brasil.
authors.forename: Vivien Thiemy
authors.initials: VT
authors.lastname: Sakai
mesh_terms: D000704:Analysis of Variance; D049109:Cell Proliferation / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D005562:Formazans; D006801:Humans; D028022:Low-Level Light Therapy / Q000379:methods*; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012235:Rhodamines; D013234:Stem Cells / Q000528:radiation effects*; D013778:Tetrazolium Salts; D013997:Time Factors; D014080:Tooth Exfoliation; D014094:Tooth, Deciduous / Q000166:cytology* / Q000528:radiation effects*
chemical_list: D005562:Formazans; D012235:Rhodamines; D013778:Tetrazolium Salts; C079782:MTT formazan; C022027:lissamine rhodamine B