title: Influence of preflaring on the accuracy of length determination with four electronic apex locators.
abstract: BACKGROUND
  The aim of this study was to compare the influence of preflaring on the accuracy of 4 electronic apex locators (EALs): Root ZX, Elements Diagnostic Unit and Apex Locator, Mini Apex Locator, and Apex DSP.
  
  
  METHODS
  Forty extracted teeth were preflared by using S1 and SX ProTaper instruments. The working length was established by reducing 1mm from the total length (TL). The ability of the EALs to detect precise (-1mm from TL) and acceptable (-1+/-0.5 mm from TL) measurements in unflared and preflared canals was determined.
  
  
  RESULTS
  The precise and acceptable (P/A) readings in unflared canals for Root ZX, Elements Diagnostic Unit and Apex Locator, Mini Apex, and Apex DSP were 50%/97.5%, 47.5%/95%, 50%/97.5%, and 45%/ 67.5%, respectively. For preflared canals, the readings were 75%/97.5%, 55%/95%, 75%/97.5%, and 60%/87.5%, respectively. For precise criteria, the preflared procedure increased the percentage of accurate electronic readings for the Root ZX and the Mini Apex Locator (P < .05). For acceptable criteria, no differences were found among Root ZX, Elements Diagnostic Unit and Apex Locator, and Mini Apex Locator (P > .05). Fisher test indicated the lower accuracy for Apex DSP (P < .05).
  
  
  CONCLUSIONS
  The Root ZX and the Mini Apex Locator devices increased significantly the precision to determine the real working length after the preflaring procedure. All the EALs showed an acceptable determination of the working length between the ranges of+/-0.5mm except for the Apex DSP device, which had the lowest accuracy.
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, São Paulo, Brazil.
authors.forename: Ericson Janolio
authors.initials: EJ
authors.lastname: de Camargo
authors.forename: Ronald Ordinola
authors.initials: RO
authors.lastname: Zapata
authors.forename: Paulo Leal
authors.initials: PL
authors.lastname: Medeiros
authors.forename: Clovis Monteiro
authors.initials: CM
authors.lastname: Bramante
authors.forename: Norberti
authors.initials: N
authors.lastname: Bernardineli
authors.forename: Roberto Brandão
authors.initials: RB
authors.lastname: Garcia
authors.forename: Ivaldo Gomes
authors.initials: IG
authors.lastname: de Moraes
authors.forename: Marco Antônio Húngaro
authors.initials: MA
authors.lastname: Duarte
mesh_terms: D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D055615:Electrical Equipment and Supplies; D006801:Humans; D009811:Odontometry / Q000295:instrumentation / Q000379:methods*; D018915:Root Canal Preparation / Q000379:methods*; D019227:Tooth Apex / Q000033:anatomy & histology*