Qualitative microanalysis of ions and ultrastructural changes in dentin exposed to laser irradiation and to metal salts solution.
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-.
Glauche
Carlos E
CE
Professional Master Course of Lasers in Dentistry, Institute of Energy and Nuclear Research, IPEN, São Paulo, SP 05508-900, Brazil.
de Freitas
Patricia M
PM
Vieira
Nilson D
ND
Marques
José Luiz Lage
JL
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*
D003802:Dentifrices; D007477:Ions; D008670:Metals; D012492:Salts; D014002:Tin Fluorides; D005461:Fluorine; D014001:Tin; C025700:strontium chloride; D013324:Strontium