title: Spiral computed tomography assessment of the efficacy of different rotary versus hand retreatment system.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the efficacy of nickel-titanium rotary retreatment systems versus stainless steel hand retreatment system with or without solvent for gutta-percha removal during retreatment.
  
  
  METHODS
  Sixty extracted human mandibular molar teeth with single canal in a distal root was prepared with ProTaper rotary nickel-titanium files and obturated with gutta-percha and sealer. The teeth were randomly divided into six groups of 10 specimens in each groups. The volume of filling material before and after retreatment were evaluated in cm(3) using the computed tomography (CT) scanner proprietary software.
  
  
  RESULTS
  Maximum amount of filling material removed during retreatment with ProTaper retreatment system with solvent and minimum with hand retreatment system with solvent.
  
  
  CONCLUSIONS
  None of the technique was 100% effective in removing the filling materials, but the ProTaper retreatment system with solvent was better.
authors.affiliation: Conservative Dentistry and Endodontics, Faculty of Dental Sciences, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
authors.forename: Neelam
authors.initials: N
authors.lastname: Mittal
authors.affiliation: Conservative Dentistry and Endodontics, Faculty of Dental Sciences, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Jain
keywords: Hand retreatment system; M-two retreatment system; ProTaper retreatment system; spiral computed tomography