title: Increase of enamel fluoride retention by low fluence argon laser beam: a 6-month follow-up study in vivo.
abstract: OBJECTIVE
  The aim of this 6-month in vivo study was to investigate if argon laser irradiation of enamel can increase the retention of fluoride.
  
  
  METHODS
  Ninety-eight teeth in 12 patients were randomly divided into three groups: (1) EF group: 40 teeth were only treated with fluoride gel (applied for 5 minutes followed by a 1 minute rinsing with distilled water). (2) EFL group: 40 teeth were treated the same way as in the EF group but they were lased after fluoridation. (3) E group: 18 teeth were kept without any treatment as a control group. In order to quantify the fluoride content in the enamel samples, the teeth were analyzed by proton beam delivered by a tandem accelerator (PIgE, particle induced gamma-ray emission). A low energy density of argon laser beam was used: 10.74 J/cm2 (11 mm of beam diameter, irradiation time of 30 seconds, and an output power of 340 mW in continuous mode).
  
  
  RESULTS
  The results after 6 months showed that the lased enamel still retained 52.55+/-8.47 ppm or 14.12% of fluoride after the fluoridation process, whereas the unlased enamel retained only 12.18+/-6.82 ppm or 3.27% of fluoride. The untreated and control enamel (E group: unlased and without fluoride treatment) had 1.16+/-4.27 ppm value of fluoride. The statistical test (ANOVA tests at 95% level) showed that the difference is significant between the fluoride retention in the group EFL and the group EF 6 months after fluoridation.
  
  
  CONCLUSIONS
  The use of argon laser at low energy density (10.74 J/cm2) significantly increased the fluoride retention in lased enamel that had approximately 400 times more fluoride than the unlased enamel. We consider this procedure as an alternative clinical procedure to increase the fluoride content of enamel surface.
authors.affiliation: Department of Dental Medicine, Faculty of Medicine, University of Liege, Liège, Belgium. s@nammour.be
authors.forename: S
authors.initials: S
authors.lastname: Nammour
authors.forename: J-P
authors.initials: JP
authors.lastname: Rocca
authors.forename: J-J
authors.initials: JJ
authors.lastname: Pireaux
authors.forename: G L
authors.initials: GL
authors.lastname: Powell
authors.forename: Y
authors.initials: Y
authors.lastname: Morciaux
authors.forename: G
authors.initials: G
authors.lastname: Demortier
mesh_terms: D000149:Acidulated Phosphate Fluoride / Q000008:administration & dosage / Q000493:pharmacokinetics*; D003731:Dental Caries / Q000517:prevention & control; D003743:Dental Enamel / Q000378:metabolism / Q000528:radiation effects*; D005500:Follow-Up Studies; D006801:Humans; D028022:Low-Level Light Therapy
chemical_list: D000149:Acidulated Phosphate Fluoride