title: Self-adjusting file cleaning-shaping-irrigation system optimizes the filling of oval-shaped canals with thermoplasticized gutta-percha.
abstract: BACKGROUND
  This study aimed to compare the filling ability of carrier-based thermoplasticized gutta-percha in flat-oval canals prepared using either rotary ProTaper files (Dentsply Maillefer, Ballaigues, Switzerland) or the Self-Adjusting File system (SAF) (ReDent-Nova, Ra'anana, Israel).
  
  
  METHODS
  Thirteen pairs of mandibular incisors were selected from a random collection. The teeth in each pair had single root canals with a flat-oval cross-section and similar sizes and dimensions. Teeth from each pair were randomly assigned to 1 of 2 experimental groups. One group was instrumented using the ProTaper NiTi system, whereas the SAF system was used in the other. Root filling was performed with Thermafil obturators (Dentsply Tulsa Dental Products, Tulsa, OK), and teeth were sectioned at 6, 5, 4, and 3 mm from the apex; the cut surface was subjected to morphometric measurement to establish the percent gutta-percha-filled area (PGFA) for each section. The Wilcoxon matched-pairs signed rank test was used to assess the effect of the 2 preparation methods on the PGFA.
  
  
  RESULTS
  The median PGFA in the ProTaper group was 77.5%, whereas the median PGFA was 90.5% in the SAF group (P < .05). In the SAF-instrumented group, 17.8% of the specimens had a PGFA ≥95% compared with only 5.8% of the ProTaper-instrumented specimens (P < .05).
  
  
  CONCLUSIONS
  Instrumentation of the flat-oval canals with the SAF system led to a significantly higher PGFA compared with ProTaper instrumentation with syringe and needle irrigation.
authors.affiliation: Department of Endodontology, Grande Rio University, Rio de Janeiro, Brazil. endogus@gmail.com
authors.forename: Gustavo
authors.initials: G
authors.lastname: De-Deus
authors.forename: Bianca
authors.initials: B
authors.lastname: Barino
authors.forename: Juliana
authors.initials: J
authors.lastname: Marins
authors.forename: Karen
authors.initials: K
authors.lastname: Magalhães
authors.forename: Erika
authors.initials: E
authors.lastname: Thuanne
authors.forename: Anda
authors.initials: A
authors.lastname: Kfir
mesh_terms: D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D006171:Gutta-Percha; D006801:Humans; D007180:Incisor; D016555:Matched-Pair Analysis; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants / Q000008:administration & dosage; D012389:Root Canal Obturation / Q000379:methods*; D018915:Root Canal Preparation / Q000295:instrumentation*; D018709:Statistics, Nonparametric
chemical_list: D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D006171:Gutta-Percha