title: [Shaping ability of two nickel-titanium rotary systems in simulated S-shaped canals].
abstract: OBJECTIVE
  To evaluate the shaping ability of two nickel-titanium rotary systems (ProTaper and Hero642) in simulated S-shaped canals.
  
  
  METHODS
  Thirty simulated S-shaped canals were randomly divided into three groups and prepared by ProTaper, Hero642, ProTaper combined with Hero642 respectively. All the canals were scanned before and after instrumentation, and the amount of material removed in the inner and outer wall and the canal width after instrumentation were measured with a computer image analysis program.
  
  
  RESULTS
  There was significant difference in the amount of material removed at the inner side of apical curvature and outer side of apex between ProTaper combined with Hero642 and ProTaper files (P < 0.05) at the same tip size. The inner and outer wall of the canals were evenly prepared by ProTaper combined with Hero642, and the taper of canals were better than those prepared by Hero642.
  
  
  CONCLUSIONS
  ProTaper combined with Hero 642 had better shaping ability to maintain the original shape and could create good taper canals in the simulated S-shaped canal model.
authors.affiliation: Department of Cariology and Endodontology, West China School of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Hong-xia
authors.initials: HX
authors.lastname: Luo
authors.forename: Ding-ming
authors.initials: DM
authors.lastname: Huang
authors.forename: Fu-hua
authors.initials: FH
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Tan
authors.forename: Xue-dong
authors.initials: XD
authors.lastname: Zhou
mesh_terms: D003722:Dental Alloys; D003762:Dental Instruments; D003786:Dental Pulp Cavity; D004868:Equipment Failure; D003765:Models, Dental; D009532:Nickel; D016382:Orthodontic Appliance Design; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium