title: A morphological in vitro study of the effects of Nd:YAG laser on irradiated cervical dentin.
abstract: OBJECTIVE
  The purpose of this in vitro study was to verify the efficacy of Nd:YAG pulsed laser at 1064 nm in sealing dentinal tubules in vitro, with its resulting morphological changes using clinical parameters applicable to the treatment of dentin hypersensitivity.
  
  
  BACKGROUND
  Although many papers have been written on the subject, no rapid, efficient, and long-lasting treatment for this problem has been developed.
  
  
  METHODS
  Twenty healthy extracted human teeth were kept in saline solution. Cervical cement was removed with a no. 57FG bur to expose approximately 4 mm(2) of dentin. Two groups were in the buccal aspect (A and B-irradiated) and one group in the lingual aspect (C-control not irradiated) of the same tooth. Samples with a remaining dentinal thickness between 1 and 1.5 mm were selected. Irradiation parameters were 30 mJ, 0.3W(Group A) and 40 mJ, 0.4 W(Group B); 7 Hz was used in both groups in two 43-sec applications each, with a 10-sec interval. In 10 samples, the dentinal surface underwent SEM examination for study. The other 10 remaining irradiated samples were centrally cleaved to study laser penetration depth in dentin (SEM).
  
  
  RESULTS
  Obliteration of dentinal tubule openings and solidification of the dentin surface were observed in all irradiated samples. Laser penetration depth in dentin (SEM) varied from 1 to 7 microm, depending on irradiation parameters used in each group.
  
  
  CONCLUSIONS
  We concluded that the use of the Nd:YAG laser was a very effective measure for obliterating dentinal tubule openings.
authors.affiliation: Mestrado Profissionalizante Lasers em Odontologia IPEN-FOUSP, São Paulo, S.P., Brazil. manoelita@uai.com.br
authors.forename: Manoelita Figueiredo
authors.initials: MF
authors.lastname: de Magalhães
authors.forename: Edmir
authors.initials: E
authors.lastname: Matson
authors.forename: Wagner
authors.initials: W
authors.lastname: de Rossi
authors.forename: José Bento
authors.initials: JB
authors.lastname: Alves
mesh_terms: D003804:Dentin / Q000473:pathology* / Q000528:radiation effects*; D006801:Humans; D053685:Laser Therapy; D008963:Molar / Q000528:radiation effects