title: Comparison of root canal preparation using Flex Master Ni-Ti and Endo-Eze AET stainless steel instruments.
abstract: OBJECTIVE
  The aim of this study was to compare various parameters of root canal preparation using FlexMaster rotary nickel-titanium and Endo-Eze AET stainless steel instruments.
  
  
  METHODS
  Fifty curved mesial root canals of extracted mandibular molars were prepared to size 45 using FlexMaster or AET instruments. The following parameters were evaluated: straightening of root canal curvature, postoperative root canal cross-sections, cleaning ability, safety issues, and working time. Statistical analyses were performed using Mann-Whitney U test and Wilcoxon test.
  
  
  RESULTS
  The mean degree of straightening was significantly less for FlexMaster than for AET (P = .001). Postoperative cross-sections showed no significant differences between the systems. Neither of the systems completely eliminated debris and smear layer. No procedural incidents occurred with the instruments. Mean working time was significantly shorter for FlexMaster than for AET (P = .0001).
  
  
  CONCLUSIONS
  AET cannot be recommended for preparation of curved root canals, owing to unacceptable straightening.
authors.affiliation: Department of Preventive Dentistry, University of Göttingen, Göttingen, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Nordmeyer
authors.forename: Véronique
authors.initials: V
authors.lastname: Schnell
authors.forename: Michael
authors.initials: M
authors.lastname: Hülsmann
mesh_terms: D054893:Cone-Beam Computed Tomography; D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000601:surgery; D004867:Equipment Design; D006801:Humans; D008334:Mandible; D008963:Molar; D009532:Nickel; D009811:Odontometry; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D016369:Smear Layer; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium