title: Time required to remove guttacore, thermafil plus, and thermoplasticized gutta-percha from moderately curved root canals with protaper files.
abstract: BACKGROUND
  A novel carrier-based obturation system, GuttaCore, was developed to facilitate more efficient nonsurgical retreatments. This ex vivo study evaluated the time required for re-treating GuttaCore and 2 other common obturation materials in moderately curved canals with ProTaper retreatment and ProTaper files.
  
  
  METHODS
  Sixty mesial roots of mandibular molars with the same mean curvature were randomly divided into 3 experimental groups: warm vertical, Thermafil Plus, and GuttaCore. Ten teeth served as positive and negative controls. The mesiobuccal canal in each sample was prepared to ISO size 30 with 0.04 taper. The warm vertical group was obturated by using a continuous-wave technique of gutta-percha compaction, and the Thermafil Plus and GuttaCore groups were obturated according to manufacturers' instructions. After allowing sealer to set, each specimen was sequentially treated with ProTaper Retreatment files D1, D2, and D3 and ProTaper Universal file F3 to the predetermined working length. The time taken to reach working length (T1) and the time required for obturation material removal (T2) were recorded.
  
  
  RESULTS
  One-way analysis of variance followed by post hoc Tukey-Kramer test indicated that the mean total time to remove filling material for the GuttaCore group was significantly shorter than those observed in the other groups (P < .05). No significant difference was observed between warm vertical and Thermafil Plus groups.
  
  
  CONCLUSIONS
  GuttaCore is removed in less time from moderately curved canals with ProTaper files than either thermoplasticized gutta-percha or Thermafil Plus materials.
authors.affiliation: Department of Endodontics, University of Iowa, Iowa City, Iowa, 52242-1001, USA.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Beasley
authors.forename: Anne E
authors.initials: AE
authors.lastname: Williamson
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Justman
authors.forename: Fang
authors.initials: F
authors.lastname: Qian
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000473:pathology*; D004853:Epoxy Resins / Q000737:chemistry; D006171:Gutta-Percha / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D008963:Molar / Q000033:anatomy & histology; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D013997:Time Factors; D019227:Tooth Apex / Q000473:pathology
chemical_list: D003432:Cross-Linking Reagents; D004853:Epoxy Resins; D012387:Root Canal Filling Materials; C534916:epoxy resin-based root canal sealer; D006171:Gutta-Percha