title: A comparative evaluation of the increase in root canal surface area and canal transportation in curved root canals by three rotary systems: A cone-beam computed tomographic study.
abstract: OBJECTIVE
  The aim of this study was to measure the increase in root canal surface area and canal transportation after biomechanical preparation at 1, 3, and 5 mm short of the apex with three different rotary systems in both continuous rotary and reciprocating rotary motions.
  
  
  METHODS
  Sixty freshly extracted human mandibular molars with mesial root canal curvatures between 20° and 30° were included in the study. Teeth were randomly distributed into three groups (n = 20). Biomechanical preparations were done in all the mesial canals. In Group 1, instrumentation was done with ProTaper universal rotary files, Group 2, with K3XF rotary files, and Group 3, with LSX rotary files. Each group was further subdivided into subgroups A and B (n = 10) where instrumentation was done by continuous rotary and reciprocating rotary techniques, respectively. Increase in root canal surface area and canal transportation was measured using the preoperative and postoperative cone-beam computed tomography scans.
  
  
  METHODS
  The data were analyzed by one-way ANOVA followed by Tukey pairwise multiple comparison tests.
  
  
  RESULTS
  Increase in root canal surface area was significantly more (P < 0.05) in ProTaper and K3XF groups when compared to LSX group. Canal transportation was significantly more (P < 0.05) in ProTaper group when compared to K3XF and LSX groups. There was no significant difference (P > 0.05) in increase of root canal surface area and canal transportation between continuous rotary and reciprocating rotary techniques for ProTaper Universal, K3XF and LSX groups.
  
  
  CONCLUSIONS
  LSX rotary system showed minimal increase of root canal surface area and minimal canal transportation when compared to ProTaper and K3XF rotary systems.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vishnu Dental College, West Godavari, Andhra Pradesh, India.
authors.forename: Nalam Nvd
authors.initials: NN
authors.lastname: Prasanthi
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vishnu Dental College, West Godavari, Andhra Pradesh, India.
authors.forename: Tanikonda
authors.initials: T
authors.lastname: Rambabu
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vishnu Dental College, West Godavari, Andhra Pradesh, India.
authors.forename: Girija S
authors.initials: GS
authors.lastname: Sajjan
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vishnu Dental College, West Godavari, Andhra Pradesh, India.
authors.forename: K Madhu
authors.initials: KM
authors.lastname: Varma
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vishnu Dental College, West Godavari, Andhra Pradesh, India.
authors.forename: R Kalyan
authors.initials: RK
authors.lastname: Satish
authors.affiliation: Department of Conservative Dentistry and Endodontics, Vishnu Dental College, West Godavari, Andhra Pradesh, India.
authors.forename: M
authors.initials: M
authors.lastname: Padmaja
keywords: Canal transportation; Ni-Ti; cone-beam computed tomography; root canal surface area