title: [Scanning electron microscopy investigation of canal cleaning after canal preparation with nickel titanium files].
abstract: BACKGROUND
  Root canal preparation is the most important phase of endodontic procedure and it consists of adequate canal space cleaning and shaping. In recent years, rotary instruments and techniques have gained importance because of the great efficacy, speed and safety of the preparation procedure.
  
  
  OBJECTIVE
  The aim of this research was to investigate the influence of different NiTi files on the canal wall cleaning quality, residual dentine debris and smear layer.
  
  
  METHODS
  The research was conducted on extracted human teeth in vitro conditions. Teeth were divided in 7 main groups depending on the kind of instruments used for root canal preparation: ProTaper, GT, ProFile, K-3, FlexMaster, hand ProTaper and hand GT. Root canal preparation was accomplished by crown-down technique. Prepared samples were assessed on scanning electron microscopy JEOL, JSM-6460 LV. The evaluation of dentine debris was done with 500x magnification, and the evaluation of smear layer with 1,000 times magnification. Quantitive assessment of dentine debris and smear layer was done according to the criteria of Hulsmann.
  
  
  RESULTS
  The least amount of debris and smear layer has been found in canals shaped with ProFile instruments, and the largest amount in canals shaped with FlexMaster instruments. Canal cleaning efficacy of hand GTand ProTaperfiles has been similar to cleaning efficacy of rotary NiTi files. Statistic analysis has shown a significant difference in amount of dentine debris and smear layer on the canal walls between sample groups. shaped with different instruments.
  
  
  CONCLUSIONS
  Completely clean canals have not been found in any tested group of instruments. The largest amount of debris and smear layer has been found in the apical third of all canals. The design and the type of endodontic instruments influence the efficacy of the canal cleaning.
authors.affiliation: Dental Clinic of Vojvodina, School of Medicine, University of Novi Sad, Novi Sad, Serbia. tanjahom@gmail.com
authors.forename: Tatjana
authors.initials: T
authors.lastname: Brkanić
authors.forename: Stojsin
authors.initials: S
authors.lastname: Ivana
authors.forename: Karolina
authors.initials: K
authors.lastname: Vukoje
authors.forename: Slavoljub
authors.initials: S
authors.lastname: Zivković
mesh_terms: D003722:Dental Alloys; D003786:Dental Pulp Cavity / Q000473:pathology*; D006801:Humans; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D016369:Smear Layer; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium