title: Two-dimensional changes and surface characteristics from an erbium laser used for root canal preparation.
abstract: OBJECTIVE
  Erbium lasers have been advocated for use in root canal because of their ability to ablate dentin and remove biologic debris in the root canal space. This study evaluated the ability of an Er:YAG laser to remove dentin predictably in the root canal system and its cleaning ability.
  
  
  METHODS
  Twenty-eight single-rooted extracted teeth were assigned into two groups. The first group was cleaned and shaped using crown-down technique with GT rotary files (control). The second group used an Er:YAG laser with ceramic tip, above the dentin ablation threshold for root canal shaping. A separate group of three teeth was evaluated for cleanliness using an Er:YAG laser with spiral tips. Amount of dentin removed in the buccal-lingual and mesial-distal directions was measured, the data analyzed by ANOVA. Surface characteristics were qualitatively examined.
  
  
  RESULTS
  The control group produced cleaner, better shaped root canals, faster than the Er:YAG group. The Er:YAG group removed more dentin in the coronal portion but less in the middle and apical thirds. The Er:YAG with spiral tip group left a dense smear layer in the middle and apical thirds. The Er:YAG group was subject to procedural errors more often than the control group.
  
  
  CONCLUSIONS
  The Erbium laser studied was equivalent to rotary files in the coronal and middle thirds but not in the apical thirds of the root canal system.
authors.affiliation: Division of Endodontics, Department of Preventive and Restorative Dental Sciences, University of California School of Dentistry, San Francisco, California 94143-0758, USA. mjroperdds@aol.com
authors.forename: M J
authors.initials: MJ
authors.lastname: Roper
authors.forename: J M
authors.initials: JM
authors.lastname: White
authors.forename: H E
authors.initials: HE
authors.lastname: Goodis
authors.forename: D
authors.initials: D
authors.lastname: Gekelman
mesh_terms: D003804:Dentin; D006801:Humans; D053844:Lasers, Solid-State; D018915:Root Canal Preparation / Q000379:methods*; D013499:Surface Properties