title: Effects of copper vapor laser irradiation in human enamel and dentin: ablation and morphological studies.
abstract: OBJECTIVE
  This investigation was performed to determine the ranges of ablation quantitatively and to evaluate the morphological changes in human enamel and dentine irradiated by a green copper vapor laser.
  
  
  BACKGROUND
  Recently, green copper vapor laser (CVL), which is said to have characteristics similar to the argon laser has been introduced in dentistry.
  
  
  METHODS
  Extracted noncarious human teeth were used in this study. A CVL was used to ablate human dental hard tissues with the output powers of 2.0 W. Ablation extent without water spray using red or black ink was measured, and the morphological changes on enamel and dentin were also investigated by stereoscopy and scanning electron microscopy (SEM).
  
  
  RESULTS
  In the samples, irradiated by a CVL after painting red ink on the surface, the ablation depth was increased more than that of irradiation after painting with black ink. Morphological findings by SEM indicated that when irradiated with red ink, brown carbonization was recognized on enamel and dentin surfaces. In addition, cavities with a molten lava-like appearance were produced and an irregular structure with many microholes was observed in the enamel and dentin. Alternatively, a shallow cavity with little carbonization was produced with black ink.
  
  
  CONCLUSIONS
  Removal of dental hard tissues appears to be possible using the CVL. However, further studies should be performed on the selection of radiation conditions that achieve the desired ablation with minimal side effects.
authors.affiliation: Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamura
authors.forename: M
authors.initials: M
authors.lastname: Hossain
authors.forename: T
authors.initials: T
authors.lastname: Joe
authors.forename: T
authors.initials: T
authors.lastname: Kawanaka
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D003300:Copper / Q000009:adverse effects*; D003731:Dental Caries / Q000209:etiology*; D003743:Dental Enamel / Q000528:radiation effects* / Q000648:ultrastructure*; D003804:Dentin / Q000528:radiation effects* / Q000648:ultrastructure*; D006801:Humans; D066298:In Vitro Techniques; D028022:Low-Level Light Therapy / Q000009:adverse effects*
chemical_list: D003300:Copper