title: Quantec SC rotary instruments versus hand files for gutta-percha removal in root canal retreatment.
abstract: OBJECTIVE
  The purpose of this study was to compare Quantec SC rotary instruments and hand files for removal of gutta-percha during retreatment.
  
  
  METHODS
  Twenty maxillary central incisors with a single straight canal were selected. The canals were instrumented and filled before the teeth were randomly divided into two groups of 10 specimens each. In group 1 Quantec SC rotary instruments were used for filling removal and in group 2, hand files and solvent. The following factors were evaluated: time taken to reach working length, time for gutta-percha removal, total time, apically extruded material during filling removal and number of fractured instruments. Radiographs were taken and the teeth were grooved longitudinally and split. The canal walls of each half and the radiographs were evaluated visually for cleanliness. They were then digitized using a scanner and the residual debris assessed. The analysis was carried out in the cervical, middle and apical thirds separately as well for the whole canal.
  
  
  RESULTS
  The time for root filling removal was significantly less when Quantec SC was used (P < 0.05). The amount of apically extruded material was not significantly different between the groups (P > 0.05). Direct evaluation of the canal walls revealed that hand files and solvent demonstrated better cleanliness in the cervical third and in whole canal (P < 0.05). Radiographic analysis demonstrated that hand files performed significantly better when viewed in a mesiodistal direction (P < 0.05).
  
  
  CONCLUSIONS
  Although Quantec SC instruments took less time, hand instruments and solvent cleaned canals more effectively.
authors.affiliation: Department of Endodontics, Bauru School of Dentistry, University of São Paulo, Brazil.
authors.forename: L V
authors.initials: LV
authors.lastname: Betti
authors.forename: C M
authors.initials: CM
authors.lastname: Bramante
mesh_terms: D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging / Q000473:pathology; D004867:Equipment Design; D004868:Equipment Failure; D005547:Foreign Bodies / Q000209:etiology; D006171:Gutta-Percha / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007180:Incisor; D008422:Materials Testing; D011859:Radiography; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000737:chemistry; D012389:Root Canal Obturation; D018915:Root Canal Preparation / Q000295:instrumentation*; D012390:Root Canal Therapy; D012399:Rotation; D012997:Solvents / Q000737:chemistry; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013997:Time Factors; D019227:Tooth Apex; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry
chemical_list: D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D012997:Solvents; D015035:Zinc Oxide-Eugenol Cement; D006171:Gutta-Percha