title: CO2 laser-irradiation through topically applied fluoride increases acid resistance of demineralised human enamel in vitro.
abstract: OBJECTIVE
  To evaluate the effect of CO2 laser treatment through topically applied amine fluoride solution on demineralised enamel.
  
  
  METHODS
  Sixty extracted human molar crowns were selected and cut longitudinally into half. One half was subjected to a 10-day pH-cycling procedure to create caries-like lesions, whereas the other was left non-demineralised. The following treatments were randomly assigned (one treatment per tooth, on respective non-demineralised and demineralised matched specimens): exposure to a 1% amine fluoride solution for 15 s without irradiation (group I), irradiation for 15 s with a continuous-wave CO2 laser (group II), or laser-treatment for 15 s through the amine fluoride solution applied immediately beforehand (group III). Fluoride uptake (n = 30) and acid resistance (n = 30) were determined after treatment. Enamel surface alterations after laser irradiation were monitored using scanning electron microscopy.
  
  
  RESULTS
  In groups I and III, an increased fluoride uptake was detected (p < or = 0.05). Laser irradiation through topical fluoride resulted in an increased acid resistance of sound and demineralised enamel specimens in deeper layers (p < or = 0.05). In addition, less surface alterations were observed in SEM examination of specimens irradiated through the amine fluoride solution compared with counterparts treated with laser only.
  
  
  CONCLUSIONS
  CO2 laser light application through an amine fluoride solution may be instrumental in enhancing acid resistance of sound and demineralised enamel.
authors.affiliation: Clinic for Preventive Dentistry, Periodontology and Cariology, Center for Dental and Oral Medicine and Cranio-Maxillofacial Surgery, Zurich, Switzerland. patrick.schmidlin@zzmk.unizh.ch
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Schmidlin
authors.forename: Iris
authors.initials: I
authors.lastname: Dörig
authors.forename: Adrian
authors.initials: A
authors.lastname: Lussi
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Roos
authors.forename: Thomas
authors.initials: T
authors.lastname: Imfeld
mesh_terms: D000704:Analysis of Variance; D003743:Dental Enamel / Q000378:metabolism; D005460:Fluorides, Topical / Q000493:pharmacokinetics / Q000627:therapeutic use*; D006801:Humans; D053685:Laser Therapy; D054020:Lasers, Gas / Q000627:therapeutic use*; D008855:Microscopy, Electron, Scanning; D008963:Molar; D017001:Tooth Demineralization / Q000188:drug therapy / Q000601:surgery / Q000628:therapy*
chemical_list: D005460:Fluorides, Topical; C094808:amine fluoride solution