title: Morphological comparative study on ablation of dental hard tissues at cavity preparation by Er:YAG and Er,Cr:YSGG lasers.
abstract: OBJECTIVE
  The purpose of this study was to evaluate morphologically the dental hard tissue ablation at the class V cavity preparation by two types of laser devices: Er:YAG and Er,Cr:YSGG lasers in vitro.
  
  
  BACKGROUND
  There have been no reports on the comparative study of dental tissue ablation at cavity preparation by Er:YAG and Er,Cr:YSGG lasers.
  
  
  METHODS
  Twenty-two extracted human mature molar teeth were used in this study and divided into two groups of 11 teeth each. The teeth of the Er:YAG laser-irradiated group were irradiated at the parameters of 250 mJ/pulse and 15 Hz with water spray, and those of the Er,Cr:YSGG laserirradiated group were irradiated at the parameters of 5 Wand 20 Hz with water spray. After cavity preparation, the teeth were dehydrated, coated with platinum, and examined by scanning electron microscopy.
  
  
  RESULTS
  Both of the laser devices were capable of ablating dental hard tissues, but similar, irregular, and rugged surface aspects with different depths were observed. Open dentinal tubules at the cavities prepared by Er,Cr:YSGG laser were more clearly visible than those prepared by Er:YAG laser. Smaller width and stripped surfaces were observed on the cavities prepared by Er,Cr:YSGG laser.
  
  
  CONCLUSIONS
  The results suggested that there is little difference between the two types of lasers-Er:YAG and Er,Cr:YSGG lasers-morphologically for class V cavity preparation, because both lasers were capable of preparing class V cavities, and the morphological features of the irradiated surfaces were very similar.
authors.affiliation: Department of Cariology & Endodontology, Showa University School of Dentistry, 2-1-1 Kitasenzoku, Ohta-ku, Tokyo 145-8515, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Harashima
authors.forename: Jun-Ichiro
authors.initials: J
authors.lastname: Kinoshita
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kimura
authors.forename: Aldo
authors.initials: A
authors.lastname: Brugnera
authors.forename: Fatima
authors.initials: F
authors.lastname: Zanin
authors.forename: Jose D
authors.initials: JD
authors.lastname: Pecora
authors.forename: Koukichi
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D003737:Dental Cavity Preparation / Q000379:methods*; D003804:Dentin / Q000473:pathology / Q000601:surgery*; D006801:Humans; D053685:Laser Therapy / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D014867:Water
chemical_list: D014867:Water