title: Physico-chemical changes of human enamel irradiated with ArF excimer laser.
abstract: OBJECTIVE
  Irradiation of tooth enamel by lasers can alter its structure and chemical composition. The purpose of this work was to determine the compositional changes and to elucidate the mechanisms of laser-enamel interaction using ArF excimer laser.
  
  
  METHODS
  Human enamel irradiated with ArF excimer laser (wavelength, 193 nm) at different fluences, was examined using X-ray diffraction, infrared (IR) spectroscopy and microprobe analysis.
  
  
  RESULTS
  Ablation without significant compositional changes in irradiated enamel was evident when low fluences (approximately 200-380 mJ/cm2) were used. However, fluences between 640 and 2,300 mJ/cm2 resulted in an increased Ca/P ratio, decreased amount of carbonate and protein, and the formation of tricalcium phosphate and tetracalcium phosphate, suggesting the involvement of a photothermal mechanism.
  
  
  CONCLUSIONS
  The results show that ArF excimer laser can alter the chemical composition and morphology of the highly mineralized (96%) dental enamel, depending on the fluence used.
authors.affiliation: Department of Prosthodontics, The Hebrew University-Hadassah School of Dental Medicine, Jerusalem, Israel. fosnat@hadassah.org.il
authors.forename: Osnat
authors.initials: O
authors.lastname: Feuerstein
authors.forename: Isaac
authors.initials: I
authors.lastname: Mayer
authors.forename: Dan
authors.initials: D
authors.lastname: Deutsch
mesh_terms: D002118:Calcium / Q000032:analysis; D002130:Calcium Phosphates / Q000032:analysis; D002254:Carbonates / Q000032:analysis; D003743:Dental Enamel / Q000737:chemistry* / Q000528:radiation effects*; D006801:Humans; D053685:Laser Therapy; D028022:Low-Level Light Therapy; D010710:Phosphates / Q000032:analysis; D010789:Phototherapy; D011506:Proteins / Q000032:analysis
chemical_list: D002130:Calcium Phosphates; D002254:Carbonates; D010710:Phosphates; D011506:Proteins; C485830:tetracalcium phosphate; C018392:tricalcium phosphate; D002118:Calcium