title: Efficacy of ultrasonic activation of NaOCl and orange oil in removing filling material from mesial canals of mandibular molars with and without isthmus.
abstract: OBJECTIVE
  The aim of this study was to evaluate the volume of remaining filling material after passive ultrasonic irrigation (PUI) of sodium hypochlorite (NaOCl) and orange oil in mesial canals of mandibular molars, with and without isthmus.
  
  
  METHODS
  Thirty mesial roots of mandibular molars were divided according to the presence or absence of isthmus. Canals were prepared and filled (Micro-CT #1). Filling was removed using rotary instruments, and specimens were sub-divided into three groups according to the irrigation procedures: Conventional - conventional irrigation with NaOCl, PUI/NaOCl - PUI of NaOCl (three activations, 20 seconds each), and PUI/orange oil - PUI of orange oil (Micro-CT#2). Specimens were enlarged using the X2 and X3 ProTaper Next instruments and submitted to the same irrigation protocols (Micro-CT #3).
  
  
  RESULTS
  No differences were found between the experimental groups in each stage of assessment (P>0.05). The volume of residual filling material was similar to that in Micro-CT #2 and Micro-CT #3, but lower than that observed in Micro-CT #1 (P<0.05). When groups were pooled according to the presence or absence of an isthmus, volume of residual filling material was higher in specimens presenting isthmus (P<0.05).
  
  
  CONCLUSIONS
  PUI of NaOCl or orange oil did not improve filling removal. Isthmus consists in an anatomical obstacle that impairs the removal of filling material.
authors.affiliation: Department of Stomatology, Federal University of Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Mirela Sangoi
authors.initials: MS
authors.lastname: Barreto
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Ricardo Abreu da
authors.initials: RA
authors.lastname: Rosa
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Manuela Favarin
authors.initials: MF
authors.lastname: Santini
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Bruno Cavalini
authors.initials: BC
authors.lastname: Cavenago
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Marco Antônio Húngaro
authors.initials: MA
authors.lastname: Duarte
authors.affiliation: Department of Stomatology, Federal University of Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Carlos Alexandre Souza
authors.initials: CA
authors.lastname: Bier
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Marcos Vinícius Reis
authors.initials: MV
authors.lastname: Só
mesh_terms: D000704:Analysis of Variance; D006801:Humans; D008334:Mandible; D008963:Molar / Q000033:anatomy & histology; D010938:Plant Oils / Q000737:chemistry*; D015203:Reproducibility of Results; D019233:Retreatment; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D012973:Sodium Hypochlorite / Q000737:chemistry*; D007507:Therapeutic Irrigation / Q000295:instrumentation / Q000379:methods; D013997:Time Factors; D014092:Tooth Root / Q000033:anatomy & histology; D014464:Ultrasonic Therapy / Q000295:instrumentation / Q000379:methods*; D055114:X-Ray Microtomography
chemical_list: D010938:Plant Oils; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; C087245:orange oil; D012973:Sodium Hypochlorite