title: Micro-computed tomographic evaluation of canal transportation instrumented by different kinematics rotary nickel-titanium instruments.
abstract: BACKGROUND
  The purpose of this study was to evaluate and compare canal transportation of curved root canals by using 3 nickel-titanium systems: Reciproc, WaveOne, and Twisted Files Adaptive (TF).
  
  
  METHODS
  Twenty-four extracted human mandibular molars with 2 separate mesial canals and severe angle of curvature were selected. Individual canals were divided randomly to 1 of the 3 experimental groups: Reciproc group, reciprocating instrumentation with Reciproc R25; WaveOne group, reciprocating instrumentation with the Primary WaveOne file; and TF Adaptive group, Adaptive Rotary Motion with the TF files. Each group consisted of 16 root canals. Specimens were scanned before and after root canal preparation with an isotropic resolution of 20 μm by using micro-computed tomography. The degree of canal transportation, in addition to instruments' centering ability, was recorded.
  
  
  RESULTS
  Less transportation occurred with TF Adaptive rotary instruments (P < .0001). The mean degree of canal transportation in the apical third was significantly lower with TF Adaptive group (P < .0001). No significant difference was found between Reciproc and WaveOne systems (P = 1.000). Mean centering ratio was the highest statistically with TF Adaptive (P < .0001), followed by WaveOne, and was minimal with Reciproc (P < .05).
  
  
  CONCLUSIONS
  The TF Adaptive system was found to have less canal transportation and better centering ability when compared with the reciprocating groups.
authors: Faculty of Dentistry, Department of Endodontics, Saint-Joseph University, Beirut, Lebanon. Electronic address: drrichardgergi@hotmail.com.
authors: Richard
authors: R
authors: Gergi
authors: Department of Endodontics, University of Brest, Brest, France.
authors: Reza
authors: R
authors: Arbab-Chirani
authors: Faculty of Dentistry, Department of Endodontics, Saint-Joseph University, Beirut, Lebanon.
authors: Nada
authors: N
authors: Osta
authors: Faculty of Dentistry, Department of Endodontics, Saint-Joseph University, Beirut, Lebanon.
authors: Alfred
authors: A
authors: Naaman
mesh_terms: D000465:Algorithms; D003722:Dental Alloys / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D004867:Equipment Design; D006801:Humans; D008963:Molar / Q000000981:diagnostic imaging; D009532:Nickel / Q000737:chemistry*; D011897:Random Allocation; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012399:Rotation; D014025:Titanium / Q000737:chemistry*; D019227:Tooth Apex / Q000000981:diagnostic imaging; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: Canal transportation; nickel-titanium; reciprocation