title: Comparative study of different novel nickel-titanium rotary systems for root canal preparation in severely curved root canals.
abstract: BACKGROUND
  We compared the effects of 6 different rotary systems on transportation, canal curvature, centering ratio, surface area, and volumetric changes of curved mesial root canals of mandibular molar via cone-beam computed tomographic (CBCT) imaging.
  
  
  METHODS
  Mesiobuccal root canals of 120 mandibular first molars with an angle of curvature ranging from 20°-40° were divided into 6 groups of 20 canals. Based on CBCT images taken before instrumentation, the groups were balanced with respect to the angle and radius of canal curvature. Root canals were shaped with the following systems with an apical size of 25: OneShape (OS) (MicroMega, Besancon, France), ProTaper Universal (PU) F2 (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Next X2 (Dentsply Maillefer), Reciproc (R) R25 (VDW, Munich, Germany), Twisted File Adaptive (TFA) SM2 (SybronEndo, Orange, CA), and WaveOne primary (Dentsply Tulsa Dental Specialties, Tulsa, OK). After root canal preparation, changes were assessed with CBCT imaging. The significance level was set at P = .05.
  
  
  RESULTS
  The R system removed a significantly higher amount of dentin than the OS, PU, and TFA systems (P < .05). There was no significant difference among the 6 groups in transportation, canal curvature, changes of surface area, and centering ratio after instrumentation.
  
  
  CONCLUSIONS
  The 6 different file systems straightened root canal curvature similarly and produced similar canal transportation in the preparation of mesial canals of mandibular molars. R instrumentation exhibited superior performance compared with the OS, TFA, and PU systems with respect to volumetric change.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey. Electronic address: capardt@hotmail.com.
authors.forename: Ismail Davut
authors.initials: ID
authors.lastname: Capar
authors.affiliation: Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
authors.forename: Huseyin
authors.initials: H
authors.lastname: Ertas
authors.affiliation: Department of Endodontics, Faculty of Dentistry, Şifa University, İzmir, Turkey.
authors.forename: Evren
authors.initials: E
authors.lastname: Ok
authors.affiliation: Department of Endodontics, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
authors.forename: Hakan
authors.initials: H
authors.lastname: Arslan
authors.affiliation: Department of Oral Diagnosis and Radiology, Faculty of Dentistry, İzmir Katip Çelebi University, İzmir, Turkey.
authors.forename: Elif Tarim
authors.initials: ET
authors.lastname: Ertas
mesh_terms: D054893:Cone-Beam Computed Tomography / Q000379:methods; D003722:Dental Alloys / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D003804:Dentin / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D008963:Molar / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009038:Motion; D009532:Nickel / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation*; D012399:Rotation; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D019227:Tooth Apex / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D019415:Torque
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: Cone-beam computed tomographic imaging; OneShape; ProTaper Next; ProTaper Universal; Reciproc; Twisted File Adaptive; WaveOne; root canal transportation; root canal volume