title: [Comparison of the shaping ability of three Ni-Ti rotary instruments in the preparation of simulated curved root canals].
abstract: OBJECTIVE
  To compare the shaping ability of three rotary Ni-Ti instruments in simulated root canals.
  
  
  METHODS
  A total of 30 simulated resin blocks were divided randomly into 3 groups: ProTaper Universal, ProTaper Next and TF Adaptive. Each group consisted of 10 root canals. The preparation time and changes in canal curvature were measured. Pre- and post-instrumentation photograghs were taken by precise camera and superimposed through Photoshop. The material removed from the inner and outer canal walls at 9 points beginning at 0 mm from the foramen were measured with Image Pro Plus. Centering ability was determined accordingly. The data was analyzed with SPSS13.0 software package.
  
  
  RESULTS
  During root canal preparation, no instruments fractured. ProTaper Next was much faster than ProTaper Universal(P<0.05). At the apical curvature, transportation was the least with TF Adaptive, followed by Protaper Next (P<0.05). There were no significant differences in 3 groups with respect to coronal curvature transportation (P>0.05).
  
  
  CONCLUSIONS
  Under the conditions of this study, ProTaper Next was the most efficient instrument. TF Adaptive and Protaper Next showed better shaping ability. In general, all the instruments respected original canal curvature well and were safe to be used.
authors.affiliation: Department of Endodontics, School of Stomatology, China Medical University. Shenyang 110002, Liaoning Province, China. E-mail:531354905@qq.com.
authors.forename: Ning
authors.initials: N
authors.lastname: Qiu
authors.affiliation: Department of Endodontics, School of Stomatology, China Medical University. Shenyang 110002, Liaoning Province, China.
authors.forename: Chu-yu
authors.initials: CY
authors.lastname: Wang
authors.affiliation: Department of Endodontics, School of Stomatology, China Medical University. Shenyang 110002, Liaoning Province, China.
authors.forename: Yu-fei
authors.initials: YF
authors.lastname: Liu
authors.affiliation: Department of Endodontics, School of Stomatology, China Medical University. Shenyang 110002, Liaoning Province, China.
authors.forename: Xiao-qing
authors.initials: XQ
authors.lastname: Yu
authors.affiliation: Department of Endodontics, School of Stomatology, China Medical University. Shenyang 110002, Liaoning Province, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Xue
mesh_terms: D003762:Dental Instruments; D003786:Dental Pulp Cavity; D006801:Humans; D009532:Nickel / Q000737:chemistry*; D018915:Root Canal Preparation / Q000379:methods*; D014025:Titanium / Q000737:chemistry*
chemical_list: C040654:titanium nickelide; D009532:Nickel; D014025:Titanium