title: Effects of ultrasonic root end preparation on resected root surfaces: SEM evaluation.
abstract: OBJECTIVE
  The purpose of this study was to investigate the in vitro effect of ultrasonic retrotips on root end surfaces.
  
  
  METHODS
  Root end resection was performed on 45 single-root teeth endodontically treated after extraction. Setting the ultrasonic device at full power, a retrograde cavity was made by a stainless steel tip in 9 specimens (SS-FP). In another 9 samples a diamond tip was used (D-FP). Setting the intensity of the ultrasonic device at half power, 9 specimens were treated using stainless steel tips (SS-HP) and 9 using diamond tip (D-HP). Nine teeth were only apically resected and used as controls. Histologic serial sections were examined by scanning electron microsope to assess the number of root-face cracking, the marginal quality, and the crack type.
  
  
  RESULTS
  No significant difference between diamond and stainless steel groups was found at a given power setting. Significant differences were found between SS-FP and SS-HP group for both the number of cracks and the marginal quality.
authors.affiliation: Section of Endodontics, Department of Odontology, Galeazzi Institute, University of Milano, Milan, Italy.
authors.forename: Silvio
authors.initials: S
authors.lastname: Taschieri
authors.forename: Tiziano
authors.initials: T
authors.lastname: Testori
authors.forename: Luca
authors.initials: L
authors.lastname: Francetti
authors.forename: Massimo
authors.initials: M
authors.lastname: Del Fabbro
mesh_terms: D000293:Adolescent; D000328:Adult; D001047:Apicoectomy; D003786:Dental Pulp Cavity / Q000293:injuries / Q000648:ultrastructure*; D003804:Dentin / Q000293:injuries / Q000648:ultrastructure; D018130:Diamond; D004867:Equipment Design; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D012184:Retrograde Obturation; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D013193:Stainless Steel; D013499:Surface Properties; D019227:Tooth Apex / Q000293:injuries / Q000648:ultrastructure*; D014464:Ultrasonic Therapy / Q000295:instrumentation / Q000379:methods*
chemical_list: D013193:Stainless Steel; D018130:Diamond