title: Efficacy of reciprocating instruments for removing filling material in curved canals obturated with a single-cone technique: a micro-computed tomographic analysis.
abstract: BACKGROUND
  The aim of this study was to evaluate the efficacy of nickel-titanium reciprocating instrument techniques and passive ultrasonic irrigation (PUI) for retreatment in curved canals and obturated with correspondent single cones.
  
  
  METHODS
  Twenty molars were selected with mesial-buccal canals with curvatures between 20° and 40°, and they were instrumented with a Reciproc R25 instrument (VDW, Munich, Germany) in a reciprocating motion and obturated with single cones and AH Plus sealer (Dentsply Maillefer, Ballaigues, Switzerland). The teeth were divided into 2 groups (n = 10) according to the instrument used for the removal of filling material: group 1: Reciproc R25 instrument and group 2: WaveOne Primary instrument (Dentsply Maillefer). The analysis of the remnant filling material was made through micro-computed tomographic imaging after the use of reciprocating instruments and again after the use of PUI with xylene. The effective time of retreatment was registered.
  
  
  RESULTS
  The filling material of the root canal was efficiently removed (P < .05) for both groups. The percentage of removal of filling materials was 93% for the Reciproc group and 92% for the WaveOne group. There were no statistical significant differences (P > .05) between the groups in relation to the removal of filling material ability and the time needed for the procedure. The effective time for the removal of filling material was 78.7 seconds and 89.5 seconds for the Reciproc and WaveOne groups, respectively.
  
  
  CONCLUSIONS
  It was concluded that both instruments efficiently but not completely removed the filling material from inside the root canals. The use of xylene with PUI increased the removal of filling material a little, but it was not statically significant.
authors.affiliation: Postgraduate Program in Endodontics, São Leopoldo Mandic Dental Research Center, Campinas, São Paulo, Brazil. Electronic address: lincolnfruchi@uol.com.br.
authors.forename: Lincoln de Campos
authors.initials: Lde C
authors.lastname: Fruchi
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Ronald
authors.initials: R
authors.lastname: Ordinola-Zapata
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Bruno Cavalini
authors.initials: BC
authors.lastname: Cavenago
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Hungaro Duarte
authors.affiliation: Postgraduate Program in Endodontics, São Leopoldo Mandic Dental Research Center, Campinas, São Paulo, Brazil.
authors.forename: Carlos Eduardo da Silveira
authors.initials: CE
authors.lastname: Bueno
authors.affiliation: Postgraduate Program in Endodontics, São Leopoldo Mandic Dental Research Center, Campinas, São Paulo, Brazil.
authors.forename: Alexandre Sigrist
authors.initials: AS
authors.lastname: De Martin
mesh_terms: D019412:Anatomy, Cross-Sectional / Q000379:methods; D003722:Dental Alloys / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004853:Epoxy Resins / Q000737:chemistry; D004867:Equipment Design; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D009038:Motion; D009532:Nickel / Q000737:chemistry; D019252:Radiography, Dental, Digital / Q000379:methods; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000737:chemistry; D012389:Root Canal Obturation / Q000379:methods*; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012973:Sodium Hypochlorite / Q000737:chemistry; D013499:Surface Properties; D007507:Therapeutic Irrigation / Q000379:methods; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000033:anatomy & histology; D019553:Tooth, Nonvital / Q000473:pathology; D000069453:Ultrasonic Waves; D055114:X-Ray Microtomography / Q000379:methods; D014992:Xylenes / Q000737:chemistry
chemical_list: D003722:Dental Alloys; D004853:Epoxy Resins; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D014992:Xylenes; C534916:epoxy resin-based root canal sealer; C040654:titanium nickelide; D009532:Nickel; D006171:Gutta-Percha; D014025:Titanium; D012973:Sodium Hypochlorite
keywords: Micro–computed tomography; reciprocating motion; root canal retreatment