title: [Ultrastructural study of sclerotic dentin surface following the application of the Er, Cr: YSGG laser].
abstract: OBJECTIVE
  To investigate the ultrastructure character of sclerotic dentin surface conditioned by the Er, Cr: YSGG laser and acid etching.
  
  
  METHODS
  Sixteen human teeth with sclerotic dentin were randomly assigned to 4 groups, and conditioned with acid etching (Group A), laser irradiation (Group B), laser irradiation after acid etching (Group C), or acid etching after laser irradiation (Group D) respectively. The characters of surface ultrastructure were observed using scanning electron microscope (SEM).
  
  
  RESULTS
  In Group A, the majority of dentin tubules were blocked by sclerotic rods. In Group B, the honeycomb-like change was found on the sclerotic dentin surface. The surface structure of Group C was similar to that of Group B. In group D etching wiped off the honeycomb-like structure.
  
  
  CONCLUSIONS
  The sclerotic dentin surface treated with laser irradiation turns into uniform honeycomb-like structure. The rough surface may be beneficial to bonding strength on sclerotic dentin after laser irradiation.
authors: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors: Xiao-Chen
authors: XC
authors: Jin
authors: Jian-Guo
authors: JG
authors: Tan
authors: Gui-Rong
authors: GR
authors: Zhang
authors: Hong
authors: H
authors: Yu
mesh_terms: D003804:Dentin / Q000528:radiation effects* / Q000648:ultrastructure*; D003809:Dentin, Secondary / Q000648:ultrastructure; D006801:Humans; D053844:Lasers, Solid-State