title: Conditioning of enamel with Nd:YAG and CO2 dental laser systems and with phosphoric acid. An in-vitro comparison of the tensile bond strength and the morphology of the enamel surface.
abstract: MATERIAL AND METHOD 1: The first stage of a three-stage in-vitro investigation used 146 maxillary incisors to identify optimum setting parameters for two CO2 and Nd:YAG standard laser systems applied in enamel conditioning for bracket bonding.
  
  
  RESULTS
  31 of the 75 parameter combinations investigated for the Nd:YAG laser and nine of the 71 investigated for the CO2 laser proved appropriate for further investigation of tensile strength. MATERIAL AND METHOD 2: In a second stage, tensile bond strength for the selected laser settings was determined in comparison to the conventional acid-etch technique for a further 210 teeth as the control group.
  
  
  RESULTS
  The highest average tensile strength for the Nd:YAG laser was 4.1 MPa, with comparable values of 3.3 MPa for the CO2 Laser and 4.9 MPa for the acid-etch technique. MATERIAL AND METHOD 3: The third stage of the investigation involved comparative scanning electron microscopy of enamel surface morphology following laser application and acid-etching.
  
  
  RESULTS
  The CO2 laser was found to produce craters of various dimensions, while the Nd:YAG laser produced honeycomb structures regionally similar to enamel samples from the acid-etch technique.
  
  
  CONCLUSIONS
  The CO2 and Nd:YAG dental lasers tested produce enamel conditioning and tensile bond strength sufficient to meet the requirements of bracket bonding.
authors.affiliation: Department of Orthodontics, University of Aachen, Germany. robertfuhrmann@web.de
authors.forename: R
authors.initials: R
authors.lastname: Fuhrmann
authors.forename: N
authors.initials: N
authors.lastname: Gutknecht
authors.forename: A
authors.initials: A
authors.lastname: Magunski
authors.forename: F
authors.initials: F
authors.lastname: Lampert
authors.forename: P
authors.initials: P
authors.lastname: Diedrich
mesh_terms: D000134:Acid Etching, Dental; D001840:Dental Bonding; D003743:Dental Enamel / Q000033:anatomy & histology; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D016910:Orthodontic Brackets; D010756:Phosphoric Acids; D013499:Surface Properties; D013718:Tensile Strength; D014016:Tissue Conditioning, Dental
chemical_list: D010756:Phosphoric Acids; C030242:phosphoric acid