title: Comparative evaluation of shaping ability of different rotary NiTi instruments in curved canals using CBCT.
abstract: OBJECTIVE
  The aim of this study was to compare the canal transportation, canal centering ability, and time taken for preparation of curved root canals after instrumentation with ProFile GT Series X (GTX) files, Revo-S files, twisted files, and Mtwo files by using cone-beam computed tomography (CBCT).
  
  
  METHODS
  Forty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20 to 40 were divided according to the instrument used in canal preparation into four groups of 10 samples each: GTX (group I), Revo-S (group II), twisted file (group III), and Mtwo (group IV). The teeth were instrumented according to manufacturer's guidelines, with all groups being prepared to size 30, 0.06 taper master apical file. Canals were scanned using an i-CAT CBCT scanner (Imaging Science International, Hatfield, PA, USA) before and after preparation to evaluate the transportation and centering ratio at 3 mm, 5 mm, 7 mm, 9 mm, and 11 mm from the apex. The data collected were evaluated using one-way analysis of variance (ANOVA) with Tukey's honestly significant difference (HSD) test.
  
  
  RESULTS
  Twisted file system showed significantly least canal transportation and highest canal centering ability values as compared to GTX, Revo-S, and Mtwo file systems. Overall, GTX, Revo-S, and Mtwo showed comparable results with respect to canal transportation and centering ability.
  
  
  CONCLUSIONS
  The innovative method of manufacturing the TF system resulted in superior shaping ability in curved canals, with the instruments remaining more centered and producing less canal transportation than GTX, Revo-S, and Mtwo file systems.
authors.affiliation: Department of Conservative Dentistry and Endodontics, I.T.S Centre for Dental Studies and Research, Delhi-Merrut Road, Ghaziabad, Uttar Pradesh, India.
authors.forename: Anshul
authors.initials: A
authors.lastname: Arora
authors.affiliation: Department of Conservative Dentistry and Endodontics, I.T.S Centre for Dental Studies and Research, Delhi-Merrut Road, Ghaziabad, Uttar Pradesh, India.
authors.forename: Sonali
authors.initials: S
authors.lastname: Taneja
authors.affiliation: Department of Conservative Dentistry and Endodontics, I.T.S Centre for Dental Studies and Research, Delhi-Merrut Road, Ghaziabad, Uttar Pradesh, India.
authors.forename: Mohit
authors.initials: M
authors.lastname: Kumar
keywords: Canal transportation; centering ability; NiTi; cone-beam computed tomograph