title: Effects of CO2 laser on fluoride uptake in enamel.
abstract: OBJECTIVE
  The objective of this study was to investigate the effects of CO(2) laser on fluoride uptake in the loosely- and firmly-bound forms in enamel.
  
  
  METHODS
  Five human molars were cut into halves before being treated with 2.0% NaF topical gel. Each half had three windows on the enamel surface, including one control and two experimental windows irradiated by two laser therapies. One half of each tooth was treated with 1 M KOH solution to remove the loosely-bound fluoride (calcium fluoride). A tooth section was obtained from each window and the relative fluorine concentration was analyzed with Secondary Ion Mass Spectrometry (SIMS). The morphology of the enamel surfaces in the windows was examined using an Environmental Scanning Electron Microscope (ESEM).
  
  
  RESULTS
  Significant laser-induced increases in the uptake of fluoride were revealed in both loosely-bound and firmly-bound apatitic fluoride, with both laser treatments (all p<0.001). Calcium fluoride-like deposits on the enamel surfaces receiving the combined laser-fluoride treatment were revealed by ESEM.
  
  
  CONCLUSIONS
  The finding of this study substantiated the laser effect in increasing the fluoride uptake into enamel.
authors.affiliation: Department of Preventive Dentistry, Faculty of Dentistry, National University of Singapore, 5 Lower Kent Ridge Road, 119074, Singapore, Singapore. pndhsus@nus.edu.sg
authors.forename: Stephen Hsu
authors.initials: SH
authors.lastname: Chin-Ying
authors.forename: Gao
authors.initials: G
authors.lastname: Xiaoli
authors.forename: Pan
authors.initials: P
authors.lastname: Jisheng
authors.forename: James S
authors.initials: JS
authors.lastname: Wefel
mesh_terms: D002245:Carbon Dioxide; D002327:Cariostatic Agents / Q000493:pharmacokinetics*; D003743:Dental Enamel / Q000378:metabolism* / Q000528:radiation effects*; D005459:Fluorides / Q000493:pharmacokinetics*; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008963:Molar; D018629:Spectrometry, Mass, Secondary Ion
chemical_list: D002327:Cariostatic Agents; D002245:Carbon Dioxide; D005459:Fluorides