title: Comparative Analysis of Canal Centering Ability of Different Single File Systems Using Cone Beam Computed Tomography- An In-Vitro Study.
abstract: BACKGROUND
  The ability of an endodontic instrument to remain centered in the root canal system is one of the most important characteristic influencing the clinical performance of a particular file system. Thus, it is important to assess the canal centering ability of newly introduced single file systems before they can be considered a viable replacement of full-sequence rotary file systems.
  
  
  OBJECTIVE
  The aim of the study was to compare the canal transportation, centering ability, and time taken for preparation of curved root canals after instrumentation with single file systems One Shape and Wave One, using cone-beam computed tomography (CBCT).
  
  
  METHODS
  Sixty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20(o) to 35(o) were divided into three groups of 20 samples each: ProTaper PT (group I) - full-sequence rotary control group, OneShape OS (group II)- single file continuous rotation, WaveOne WO - single file reciprocal motion (group III). Pre instrumentation and post instrumentation three-dimensional CBCT images were obtained from root cross-sections at 3mm, 6mm and 9mm from the apex. Scanned images were then accessed to determine canal transportation and centering ability. The data collected were evaluated using one-way analysis of variance (ANOVA) with Tukey's honestly significant difference test.
  
  
  RESULTS
  It was observed that there were no differences in the magnitude of transportation between the rotary instruments (p >0.05) at both 3mm as well as 6mm from the apex. At 9 mm from the apex, Group I PT showed significantly higher mean canal transportation and lower centering ability (0.19±0.08 and 0.39±0.16), as compared to Group II OS (0.12±0.07 and 0.54±0.24) and Group III WO (0.13±0.06 and 0.55±0.18) while the differences between OS and WO were not statistically significant.
  
  
  CONCLUSIONS
  It was concluded that there was minor difference between the tested groups. Single file systems demonstrated average canal transportation and centering ability comparable to full sequence Protaper system in curved root canals.
authors.affiliation: Reader, Department of Conservative Dentistry & Endodontics, Sri Aurobindo College of Dentistry , Indore, Madhya Pradesh, India .
authors.forename: Rolly S
authors.initials: RS
authors.lastname: Agarwal
authors.affiliation: Reader, Department of Prosthodontics, Sri Aurobindo College of Dentistry , Indore, Madhya Pradesh, India .
authors.forename: Jatin
authors.initials: J
authors.lastname: Agarwal
authors.affiliation: Professor, Department of Conservative Dentistry & Endodontics, Sri Aurobindo College of Dentistry , Indore, Madhya Pradesh, India .
authors.forename: Pradeep
authors.initials: P
authors.lastname: Jain
authors.affiliation: Professor, Department of Conservative Dentistry & Endodontics, Faculty of Dentistry, King George Medical University , Lucknow, Uttar Pradesh, India .
authors.forename: Anil
authors.initials: A
authors.lastname: Chandra
keywords: CBCT; Canal transportation; Centering ability; Single file system