title: Analysis of four gutta-percha techniques used to fill mesial root canals of mandibular molars.
abstract: OBJECTIVE
  To compare the percentage of gutta-percha, sealer and voids and the influence of isthmuses in mesial root canals of mandibular molars filled with different techniques.
  
  
  METHODS
  Canals in 60 mesial roots of mandibular first molars were prepared with ProTaper instruments to size F2 (size 25, 0.08 taper) and filled using a single-cone, lateral compaction, System B or Thermafil techniques. An epoxy resin sealer was labelled with Rhodamine-B dye to allow analysis under a confocal microscope. The percentage of gutta-percha, sealer and area of voids was calculated at 2, 4 and 6 mm from the apex, using Image Tool 3.0 software. Statistical analysis was performed using nonparametric Kruskal-Wallis and Dunn tests (P < 0.05). The influence of isthmuses on the presence or absence of voids was evaluated using the Fisher test.
  
  
  RESULTS
  At the 2 mm level, the percentage of gutta-percha, sealer and voids was similar amongst the System B, lateral compaction and single-cone techniques. The single-cone technique revealed significantly less gutta-percha, more sealer and voids in comparison with the Thermafil technique at the 2 and 4 mm level (P < 0.05). The analysis of all sections (2, 4 and 6 mm) revealed that more gutta-percha and less sealer and voids were found in root canals filled with Thermafil and System B techniques (P < 0.05). The Fisher test revealed that the presence of isthmuses increased the occurrence of voids in the lateral compaction group only (P < 0.05).
  
  
  CONCLUSIONS
  Gutta-percha, sealer filled area and voids were dependent on the canal-filling technique. The presence of isthmuses may influence the quality of root filling.
authors.affiliation: Department of Operative Dentistry, Dental Materials and Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: M A
authors.initials: MA
authors.lastname: Marciano
authors.forename: R
authors.initials: R
authors.lastname: Ordinola-Zapata
authors.forename: T V R N
authors.initials: TV
authors.lastname: Cunha
authors.forename: M A H
authors.initials: MA
authors.lastname: Duarte
authors.forename: B C
authors.initials: BC
authors.lastname: Cavenago
authors.forename: R B
authors.initials: RB
authors.lastname: Garcia
authors.forename: C M
authors.initials: CM
authors.lastname: Bramante
authors.forename: N
authors.initials: N
authors.lastname: Bernardineli
authors.forename: I G
authors.initials: IG
authors.lastname: Moraes
mesh_terms: D016009:Chi-Square Distribution; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D006171:Gutta-Percha; D006801:Humans; D008334:Mandible; D018613:Microscopy, Confocal; D008963:Molar; D012389:Root Canal Obturation / Q000379:methods*; D018709:Statistics, Nonparametric
chemical_list: D006171:Gutta-Percha