title: Efficacy of CM-Wire, M-Wire, and Nickel-Titanium Instruments for Removing Filling Material from Curved Root Canals: A Micro-Computed Tomography Study.
abstract: BACKGROUND
  The aim of this ex vivo study was to evaluate the removal of filling material after using CM-wire, M-wire, and nickel-titanium instruments in both reciprocating and rotary motions in curved canals.
  
  
  METHODS
  Thirty maxillary lateral incisors were divided into 9 groups according to retreatment procedures: Reciproc R25 followed by Mtwo 40/.04 and ProDesign Logic 50/.01 files; ProDesign R 25/.06 followed by ProDesign Logic 40/.05 and ProDesign Logic 50/.01 files; and Gates-Glidden drills, Hedström files, and K-files up to apical size 30 followed by K-file 40 and K-file 50 up to the working length. Micro-computed tomography scans were performed before and after each reinstrumentation procedure to evaluate root canal filling removal. Statistical analysis was performed with Kruskal-Wallis, Friedman, and Wilcoxon tests (P < .05).
  
  
  RESULTS
  No significant differences in filling material removal were found in the 3 groups of teeth. The use of Mtwo and ProDesign Logic 40/.05 rotary files did not enhance filling material removal after the use of reciprocating files. The use of ProDesign Logic 50/.01 files significantly reduced the amount of filling material at the apical levels compared with the use of reciprocating files.
  
  
  CONCLUSIONS
  Association of reciprocating and rotary files was capable of removing a large amount of filling material in the retreatment of curved canals, irrespective of the type of alloy of the instruments. The use of a ProDesign Logic 50/.01 file for apical preparation significantly reduced the amount of remnant material in the apical portion when compared with reciprocating instruments.
authors.affiliation: Department of Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil. Electronic address: clarissateles@usp.br.
authors.forename: Clarissa Teles
authors.initials: CT
authors.lastname: Rodrigues
authors.affiliation: Department of Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Marco Antonio Hungaro
authors.initials: MA
authors.lastname: Duarte
authors.affiliation: Department of Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Marcela Milanezi
authors.initials: MM
authors.lastname: de Almeida
authors.affiliation: Department of Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Flaviana Bombarda
authors.initials: FB
authors.lastname: de Andrade
authors.affiliation: Department of Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
authors.forename: Norberti
authors.initials: N
authors.lastname: Bernardineli
mesh_terms: D003722:Dental Alloys / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D009532:Nickel / Q000737:chemistry*; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation*; D014025:Titanium / Q000737:chemistry*; D019227:Tooth Apex / Q000000981:diagnostic imaging; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D003722:Dental Alloys; D012387:Root Canal Filling Materials; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium
keywords: Controlled memory wire; curved root canals, micro-computed tomography; reciprocating systems; root canal retreatment; rotary systems