title: Ultrastructural analysis of bone tissue irradiated by Er:YAG Laser.
abstract: OBJECTIVE
  The use of erbium:yttrium aluminum garnet (Er:YAG) laser has been suggested for bone ablation, however, little is known about the nature of the tissue after irradiation. This study was aimed to analyze the ultrastructure of bone tissue treated with Er:YAG laser, as compared to those treated with CO(2) laser and bur drilling.
  
  
  METHODS
  Parietal bones of Wistar rats were treated and analyzed by light microscopy, transmission electron microscopy (TEM), electron diffraction analysis and energy dispersive X-ray spectroscopy (SEM-EDX).
  
  
  RESULTS
  This study demonstrated that Er:YAG laser irradiation resulted in a very thin changed layer of approximately 30 microm thickness, which consisted of two distinct sub-layers: a superficial, greatly altered layer and a deep, less affected layer.
  
  
  CONCLUSIONS
  The major changes found on bone surface after Er:YAG laser irradiation consisted of micro-cracking, disorganization, and slight recrystallization of the original apatites and reduction of surrounding organic matrix.
authors.affiliation: Periodontology, Department of Hard Tissue Engineering, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8549, Japan. sasaki.peri@tmd.ac.jp
authors.forename: Katia M
authors.initials: KM
authors.lastname: Sasaki
authors.forename: Akira
authors.initials: A
authors.lastname: Aoki
authors.forename: Shizuko
authors.initials: S
authors.lastname: Ichinose
authors.forename: Isao
authors.initials: I
authors.lastname: Ishikawa
mesh_terms: D000818:Animals; D001847:Bone Diseases / Q000473:pathology* / Q000601:surgery*; D001842:Bone and Bones / Q000528:radiation effects* / Q000648:ultrastructure*; D002245:Carbon Dioxide / Q000009:adverse effects*; D004195:Disease Models, Animal; D004871:Erbium / Q000009:adverse effects*; D007834:Lasers / Q000009:adverse effects*; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011832:Radiation Injuries / Q000209:etiology* / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D013052:Spectrometry, X-Ray Emission; D013997:Time Factors; D015019:Yttrium / Q000009:adverse effects*
chemical_list: D002245:Carbon Dioxide; D015019:Yttrium; D004871:Erbium