title: Shaping ability of four nickel-titanium rotary instruments in simulated S-shaped canals.
abstract: BACKGROUND
  The purpose of this study was to compare the shaping ability of ProTaper, Mtwo, BioRaCe, and BioRaCe + S-Apex instruments in simulated canals with an S-shaped curvature.
  
  
  METHODS
  Canal transportation and aberrations were assessed by comparing the preinstrumentation and postinstrumentation images under a stereomicroscope. Analysis of variance and post hoc Student-Newman-Keuls test were used for statistical analysis.
  
  
  RESULTS
  ProTaper instruments caused more pronounced canal transportation in the apical curvature (P < .01) than all other instruments. The use of ProTaper, Mtwo, and BioRaCe instruments resulted in more canal aberrations compared with BioRaCe + S-Apex (P < .05).
  
  
  CONCLUSIONS
  NiTi systems including less tapered and more flexible instruments like S-Apex seem to be favorable when preparing S-shaped canals.
authors.affiliation: endomaterials@fastwebnet.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Bonaccorso
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cantatore
authors.forename: Guglielmo Guido
authors.initials: GG
authors.lastname: Condorelli
authors.forename: Edgar
authors.initials: E
authors.lastname: Schäfer
authors.forename: Teresa Roberta
authors.initials: TR
authors.lastname: Tripi
mesh_terms: D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D003765:Models, Dental; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D014025:Titanium; D019227:Tooth Apex / Q000033:anatomy & histology
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium