title: Comparison of air-driven vs electric torque control motors on canal centering ability by ProTaper NiTi rotary instruments.
abstract: OBJECTIVE
  Cleaning and shaping is one of the most important phases in root canal therapy. Various rotary NiTi systems minimize accidents and facilitate the shaping process. Todays NiTi files are used with air-driven and electric handpieces. This study compared the canal centering after instrumentation using the ProTaper system using Endo IT, electric torque-control motor, and NSK air-driven handpiece.
  
  
  METHODS
  This ex vivo randomized controlled trial study involved 26 mesial mandibular root canals with 10 to 35° curvature. The roots were randomly divided into 2 groups of 13 canals each. The roots were mounted in an endodontic cube with acrylic resin, sectioned horizontally at 2, 6 and 10 mm from the apex and then reassembled. The canals were instrumented according to the manufacturer's instructions using ProTaper rotary files and electric torque-control motors (group 1) or air-driven handpieces (group 2). Photographs of the cross-sections included shots before and after instrumentation, and image analysis was performed using Photoshop software. The centering ability and canal transportation was also evaluated. Repeated measurement and independent t-test provided statistical analysis of canal transportation.
  
  
  RESULTS
  The comparison of the rate of transportation toward internal or external walls between the two groups was not statistically significant (p = 0.62). Comparison of the rate of transportation of sections within one group was not significant (p = 0.28).
  
  
  CONCLUSIONS
  Use of rotary NiTi file with either electric torquecontrol motor or air-driven handpiece had no effect on canal centering.
  
  
  CONCLUSIONS
  NiTi rotary instruments can be used with air-driven motors without any considerable changes in root canal anatomy, however it needs the clinician to be expert.
authors.affiliation: Department of Endodontics, Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mina
authors.initials: M
authors.lastname: Zarei
authors.forename: Maryam
authors.initials: M
authors.lastname: Javidi
authors.forename: Mahdi
authors.initials: M
authors.lastname: Erfanian
authors.forename: Mahdi
authors.initials: M
authors.lastname: Lomee
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Afkhami
mesh_terms: D000388:Air; D003722:Dental Alloys / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D003804:Dentin / Q000648:ultrastructure; D055615:Electrical Equipment and Supplies; D004867:Equipment Design; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008963:Molar / Q000033:anatomy & histology; D009532:Nickel / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012399:Rotation; D014025:Titanium / Q000737:chemistry*; D019227:Tooth Apex / Q000033:anatomy & histology; D014092:Tooth Root / Q000033:anatomy & histology; D019415:Torque
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium