title: Change of enamel after Er:YAG and CO2 laser irradiation and fluoride treatment.
abstract: OBJECTIVE
  Our aim was to compare acquired acid resistance in dental enamel after Er:YAG and CO(2) laser irradiation in vitro with additional fluoride treatment.
  
  
  BACKGROUND
  The application of lasers in dental hard tissue can impact dental constituents and fluoride with complex interactions.
  
  
  METHODS
  Bovine enamels were divided into four groups according to their surface condition: unlased, Er:YAG laser-ablated, fluoridetreated after Er:YAG laser ablation, and CO(2) laser-irradiated after Er:YAG laser and fluoride treatment. Calcium distribution in enamel after pH-cycling process and crystallographical change after laser treatment were evaluated.
  
  
  RESULTS
  The crystallinity of enamel was much improved after Er:YAG laser ablation. The CO(2) laser irradiation in the fluoride-treated laser enamel formed alpha-TCP and fluorapatite. The change of calcium distribution in enamel was least in the CO(2) laser-irradiated specimens; the fluoride-treated specimen after Er:YAG laser ablation was next. Additional fluoride treatment both after Er:YAG and before CO(2) laser irradiation improved the acid resistance of enamel.
  
  
  CONCLUSIONS
  Both external treatment of fluoride and irradiation of CO(2) laser after Er:YAG laser ablation greatly reduced calcium loss in enamel during the pH cycling process.
authors.affiliation: Department of Dental Materials, College of Dentistry and Medical Research Institute, Pusan National University, Pusan, South Korea.
authors.forename: Yong Hoon
authors.initials: YH
authors.lastname: Kwon
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Lee
authors.forename: Youn-Hee
authors.initials: YH
authors.lastname: Choi
authors.forename: Jae-Mok
authors.initials: JM
authors.lastname: Lee
authors.forename: Keun-Bae
authors.initials: KB
authors.lastname: Song
mesh_terms: D000143:Acids / Q000009:adverse effects; D000818:Animals; D002327:Cariostatic Agents / Q000494:pharmacology*; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects* / Q000528:radiation effects*; D053685:Laser Therapy / Q000295:instrumentation*; D012969:Sodium Fluoride / Q000494:pharmacology*; D017001:Tooth Demineralization / Q000209:etiology / Q000517:prevention & control
chemical_list: D000143:Acids; D002327:Cariostatic Agents; D012969:Sodium Fluoride