title: Efficacy of two rotary systems in removing gutta-percha and sealer from the root canal walls.
abstract: BACKGROUND
  The aim of this in vitro study was to compare the efficacy of two retreatment rotary systems in removal of gutta-percha (GP) and sealer from the root canal walls with and without use of solvent.
  
  
  METHODS
  Sixty single-canalled distal roots of mandibular molars were prepared and root filled with gutta-percha and AH26. Each canal was randomly allocated to receive one of the retreatment techniques, Mtwo R or ProTaper. The groups were further divided into two subgroups: with or without the use of solvent. The cleanliness of canal walls was determined by stereomicroscope and scanning electron microscopy.
  
  
  RESULTS
  The results showed that Mtwo R without the use of solvent was more efficient in material removal compared to ProTaper D (P<0.05). Most remnants were found in the apical third of the canals (P<0.05).
  
  
  CONCLUSIONS
  Mtwo R seems to be an efficient rotary system for endodontic retreatment of root canal with GP.
authors.affiliation: Department of Endodontics, Dental School, Islamic Azad University of Medical sciences, Tehran, Iran.
authors.forename: Bahareh
authors.initials: B
authors.lastname: Dadresanfar
authors.forename: Payman
authors.initials: P
authors.lastname: Mehrvarzfar
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Saghiri
authors.forename: Sedigh
authors.initials: S
authors.lastname: Ghafari
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Khalilak
authors.forename: Mehdi
authors.initials: M
authors.lastname: Vatanpour
keywords: Gutta-Percha; Mtwo R; Protaper D Series; Retreatment; SEM