title: Effect of GaAIAs laser on reactional dentinogenesis induction in human teeth.
abstract: OBJECTIVE
  This study investigated the biomodulatory effect of the gallium- aluminum-arsenate laser (GaAlAs) in pulp cells on reactional dentinogenesis, and on the expression of collagen type III (Col III), tenascin (TN), and fibronectin (FN) in irradiated dental tissues and controls (not irradiated).
  
  
  BACKGROUND
  Several studies suggest a biomodulatory influence of low-intensity laser radiation in the inflammatory and reparative processes of biological tissues.
  
  
  METHODS
  Sixteen human premolar teeth were selected (after extraction due to orthodontal reasons) and divided into irradiated and control groups. Black class V cavity preparations were accomplished in both groups. For the irradiated group, GaAlAs laser (670 nm, 50 mW) with an energy density of 4 J/cm2 was used. Soon after, the cavities were restored with a glass ionomer and the extractions made after 14 and 42 days.
  
  
  RESULTS
  Histological changes were observed by light microscopy; less intense inflammatory reaction in the irradiated group was found when compared to the controls. Only the irradiated group of 42 days exhibited an area associated with reactional dentinogenesis. After immunohistochemical analysis by the streptoavidin-biotin complex (SABC) method, the expression of Col III, TN, and FN was greater in the irradiated groups.
  
  
  CONCLUSIONS
  Our results suggest that a GaAlAs laser with energy density of 4 J/cm2 and wavelength of 670 nm caused biomodulation in pulp cells and expression of collagen, but not collagen of the extracellular matrix, after preparation of a cavity.
authors.affiliation: Group of Biomolecular Spectroscopy, Institute of Research and Development (IP&D), University of Vale do Paraíba (UNIVAP), São José dos Campos, Brazil. andriananayme@uol.com.br
authors.forename: Adriana Nayme Segovia
authors.initials: AN
authors.lastname: Ferreira
authors.forename: Landulfo
authors.initials: L
authors.lastname: Silveira
authors.forename: Walter João
authors.initials: WJ
authors.lastname: Genovese
authors.forename: Vera Cavalcante
authors.initials: VC
authors.lastname: de Araújo
authors.forename: Lúcio
authors.initials: L
authors.lastname: Frigo
authors.forename: Ricardo Alves
authors.initials: RA
authors.lastname: de Mesquita
authors.forename: Eduardo
authors.initials: E
authors.lastname: Guedes
mesh_terms: D000535:Aluminum; D001149:Arsenates; D001641:Bicuspid / Q000528:radiation effects; D024061:Collagen Type III / Q000378:metabolism; D003782:Dental Pulp / Q000378:metabolism / Q000528:radiation effects; D003810:Dentinogenesis / Q000528:radiation effects*; D005353:Fibronectins / Q000378:metabolism; D005708:Gallium; D006801:Humans; D007150:Immunohistochemistry; D028022:Low-Level Light Therapy; D019063:Tenascin / Q000378:metabolism
chemical_list: D001149:Arsenates; D024061:Collagen Type III; D005353:Fibronectins; D019063:Tenascin; D005708:Gallium; D000535:Aluminum