title: Preparation of the coronal and middle third of oval root canals with a rotary or an oscillating system.
abstract: OBJECTIVE
  To comparatively evaluate the preparation of oval root canals with a rotary or an oscillating system.
  
  
  METHODS
  The middle and coronal parts of 55 extracted permanent teeth with oval canals were prepared using FlexMaster (FM) rotary NiTi instruments and EndoEze AET (EE) stainless steel oscillating instruments. Pre- and postoperative images of cross-sections were superimposed to identify shifts in the center and to assess the percentage of untreated regions. In addition, the middle segment was investigated by scanning electron microscope (SEM) to determine debris and smear layer removal.
  
  
  RESULTS
  The systems did not significantly differ in the shifts of the canal centers in the middle part of the root. Only a few of the preparations yielded an excellent result with no uninstrumented canal wall left. The SEM investigation demonstrated poor results for both systems regarding debris and smear layer removal, but no significant differences could be observed.
  
  
  CONCLUSIONS
  Neither FM nor EE was capable of completely preparing oval root canals.
authors: Department of Operative/Preventive Dentistry and Endodontics, University of Düsseldorf, Düsseldorf, Germany. stefan.ruettermann@uni-duesseldorf.de
authors: Stefan
authors: S
authors: Rüttermann
authors: Anca
authors: A
authors: Virtej
authors: Ralf
authors: R
authors: Janda
authors: Wolfgang H-M
authors: WH
authors: Raab
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D003804:Dentin / Q000648:ultrastructure; D019229:Dentition, Permanent; D006801:Humans; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012399:Rotation; D016037:Single-Blind Method; D016369:Smear Layer