title: Qualitative microanalysis of ions and ultrastructural changes in dentin exposed to laser irradiation and to metal salts solution.
abstract: OBJECTIVE
  This study evaluated the ultrastructural changes in dentin after treatment with the Nd:YAG laser and/or metal salt solutions and verified the presence of Sn++, Sr++, and F- in dentin structure.
  
  
  METHODS
  Sixty dentin disks were randomly divided into groups (n = 10): (I) control (no treatment), (II) Nd:YAG (1.5 W, 100 mJ, 15 Hz, 125 J/cm2), (III) 10% SnF2 aqueous solution for 30 minutes, (IV) Nd:YAG+10% SnF2 aqueous solution for 30 minutes, (V) 10% SrCl2 toothpaste for 30 minutes, (VI) Nd:YAG+10% SrCl2 toothpaste for 30 minutes. Then, all samples were prepared for scanning electron microscopy (SEM) and the samples from Groups I to IV for the energy dispersive X-ray microanalysis (EDX).
  
  
  RESULTS
  SEM evaluation revealed occluded dentinal tubules and a dentin surface altered by the laser irradiation. The EDX microanalysis revealed Sn++ at a depth of 250 microm in Group IV and not deeper than 100 microm in Group III. In Group V, Sr++ was not deeper than 50 microm, but it could be detected at a depth of 500 microm in Group VI. F- was found only in Group IV.
  
  
  CONCLUSIONS
  Ultrastructural changes caused by laser irradiation can increase dentin uptake of Sn++, Sr++, and F-.
authors.affiliation: Professional Master Course of Lasers in Dentistry, Institute of Energy and Nuclear Research, IPEN, São Paulo, SP 05508-900, Brazil.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Glauche
authors.forename: Patricia M
authors.initials: PM
authors.lastname: de Freitas
authors.forename: Nilson D
authors.initials: ND
authors.lastname: Vieira
authors.forename: José Luiz Lage
authors.initials: JL
authors.lastname: Marques
mesh_terms: D003802:Dentifrices / Q000494:pharmacology*; D003804:Dentin / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D003806:Dentin Permeability / Q000187:drug effects / Q000528:radiation effects; D003807:Dentin Sensitivity; D005461:Fluorine / Q000502:physiology; D006801:Humans; D007477:Ions / Q000378:metabolism; D053685:Laser Therapy; D008670:Metals / Q000494:pharmacology; D012492:Salts / Q000494:pharmacology; D013324:Strontium / Q000494:pharmacology* / Q000502:physiology; D014001:Tin / Q000502:physiology; D014002:Tin Fluorides / Q000494:pharmacology*
chemical_list: D003802:Dentifrices; D007477:Ions; D008670:Metals; D012492:Salts; D014002:Tin Fluorides; D005461:Fluorine; D014001:Tin; C025700:strontium chloride; D013324:Strontium