title: The shaping effects of three nickel-titanium rotary instruments on preparing curved canals in posterior teeth.
abstract: OBJECTIVE
  To investigate the shaping effects of three nickel-titanium rotary instruments on preparing curved canals in posterior teeth.
  
  
  METHODS
  64 curved mesial canals of extracted lower molars, embedded in the Branmante models, were randomly assigned to four groups: (1) Flexofile; (2) LightSpeed; (3) ProFile; (4) Qantec SC. Apical preparation was carried out till size 30. The area of dentine removal, least remaining dentine thickness and transportation of canal center were measured.
  
  
  RESULTS
  Flexofile resulted in more dentine removal and canal center transportation than LightSpeed and ProFile (P < 0.05) at the apical and mid-root levels. In the mid-root sections, Flexofile left the thinnest dental wall in the distal aspect; 87% of the canal centers in the Flexofile group were transported in a distal direction as compared with one third in other groups.
  
  
  CONCLUSIONS
  LightSpeed and ProFile exhibited better shaping ability than Flexofile in preparing curved canals.
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua College of Stomatology, Zhongshan University, Guangzhou 510055, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Wei
authors.forename: Junqi
authors.initials: J
authors.lastname: Ling
authors.forename: Shunbin
authors.initials: S
authors.lastname: Zhang
mesh_terms: D003722:Dental Alloys; D003762:Dental Instruments / Q000592:standards*; D006801:Humans; D008963:Molar; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D014025:Titanium
chemical_list: D003722:Dental Alloys; D009532:Nickel; D014025:Titanium