title: Morphological analysis of cementum and root dentin after Er:YAG laser irradiation.
abstract: OBJECTIVE
  To investigate the morphology of cementum and root dentin after Er:YAG laser irradiation with and without water coolant, compared to that after CO(2) laser irradiation and an untreated surface.
  
  
  METHODS
  Ten extracted healthy human teeth were used. Er:YAG and CO(2) lasers were applied with energy outputs of 0.4 W, with and without coolant and 0.5 W, without coolant, respectively. Scanning electron microscopy (SEM) analysis was performed at high and ultra-high magnifications.
  
  
  RESULTS
  The surface of cementum was micro-irregular with numerous projections while that of dentin appeared scaly after Er:YAG laser irradiation. Unlike after CO(2) laser treatment, no major melting or cracking was observed with Er:YAG laser treatment. The use of water spray produced fine micro-irregularities without attached debris. Ultra-high magnification revealed similar microparticles-composed aspects for both cementum and dentin. However, the more porous structure of the surface was observed after Er:YAG laser irradiation without water spray.
  
  
  CONCLUSIONS
  Cementum and root dentin presented distinct micro-roughness after Er:YAG laser irradiation, possibly due to structural differences in the original tissue. However, under ultra-high magnifications, both cementum and dentin presented similar characteristics of the irradiated surface. In addition, the use of water spray during laser irradiation minimized thermal effects and resulted in a cleaner and less porous surface.
authors.affiliation: Division of Periodontology, Department of Hard Tissue Engineering, Graduate School, Tokyo Medical and Dental University, Tokyo, 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: D003739:Dental Cementum / Q000528:radiation effects* / Q000648:ultrastructure*; D003804:Dentin / Q000528:radiation effects* / Q000648:ultrastructure*; D006801:Humans; D066298:In Vitro Techniques; D028022:Low-Level Light Therapy; D008855:Microscopy, Electron, Scanning; D010510:Periodontal Diseases / Q000517:prevention & control* / Q000532:radiotherapy*; D014867:Water / Q000494:pharmacology
chemical_list: D014867:Water