title: Efficacy of root canal preparation by Er,Cr:YSGG laser irradiation with crown-down technique in vitro.
abstract: OBJECTIVE
  The purpose of this study was to compare the efficacy of Er,Cr:YSGG laser in root canal preparation and its effectiveness in removing debris and smear layer with the efficacy of the conventional hand instrument, in vitro.
  
  
  BACKGROUND
  Recently, the use of the Er,Cr:YSGG laser device in root canal preparation has been excepted in the dental clinic. However, there have been no published reports on root canal preparation by using the Er,Cr:YSGG laser irradiation.
  
  
  METHODS
  A total of 40 straight root canals were prepared by an Er,Cr:YSGG laser at a output power of 2 W, and 40 canals were shaped by using the K file under irrigation with NaOCl and H2O2 by using the crown-down technique (control). The achievement degree of root canal preparation and debris score was morphologically investigated.
  
  
  RESULTS
  The results showed that great improvement in the cleanliness of the walls was found using the laser technique as compared with the control technique; a significant decrease in smear layer or debris was also recognized in laser-prepared canals (p < 0.01). But canal preparations with the laser device sometime result in ledge, zipped, perforation, or over-instrumentation.
  
  
  CONCLUSIONS
  The results demonstrated that root canal preparations with the laser device were significantly worse than in the control group. Further development in laser device and technique are required to ensure its success in root canal preparation.
authors.affiliation: Department of Endodontics, Showa University School of Dentistry, Tokyo, Japan. thebestdentist@yahoo.com
authors.forename: Mir Nowazesh
authors.initials: MN
authors.lastname: Ali
authors.forename: Mozammal
authors.initials: M
authors.lastname: Hossain
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Emi
authors.initials: E
authors.lastname: Matsuoka
authors.forename: Jun-Ichiro
authors.initials: J
authors.lastname: Kinoshita
authors.forename: Koukichi
authors.initials: K
authors.lastname: Matsumoto
mesh_terms: D000891:Anti-Infective Agents, Local / Q000008:administration & dosage; D016022:Case-Control Studies; D003786:Dental Pulp Cavity / Q000528:radiation effects*; D003804:Dentin / Q000528:radiation effects; D004202:Disinfectants / Q000008:administration & dosage; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage; D066298:In Vitro Techniques; D053685:Laser Therapy; D008855:Microscopy, Electron, Scanning; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000008:administration & dosage; D013499:Surface Properties; D014092:Tooth Root / Q000528:radiation effects*
chemical_list: D000891:Anti-Infective Agents, Local; D004202:Disinfectants; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite