title: Evaluation of the Joypex 5 and Root ZX II: an in vivo and ex vivo study.
abstract: OBJECTIVE
  To evaluate in vivo and ex vivo the accuracy of the multifrequency electronic root canal length measurement device (ERCLMD) Joypex 5 and compare it with the Root ZX II. The ex vivo methodology for evaluation of the accuracy of ERCLMDs was also validated by comparison with in vivo results.
  
  
  METHODS
  Twenty single-rooted human teeth that were scheduled for extraction were selected. Working length measurements were performed in vivo with the Joypex 5 and Root ZX II. After the teeth were extracted, each canal was measured with the ERCLMDs ex vivo. Then, a size 15 K-file was used to determine the reference working length (RWL), which was established 0.5 mm from the major foramen by direct observation. The measurements of working length obtained with the different methods and ERCLMDs were compared by analysis of variance and Tukey's test at P < .05. Statistical correlations were also performed.
  
  
  RESULTS
  No significant difference was observed between in vivo and ex vivo measurements or the different types of ERCLMDs. The Bland-Altman plot confirmed the agreement of different methods and ERCLMDs to measure canal length. The R(2) coefficient obtained in both situations, comparing the ERCLMDs, was close to 1, denoting a strong agreement between measurements obtained with the Joypex 5 and Root ZX II and between in vivo and ex vivo methodologies.
  
  
  CONCLUSIONS
  The Joypex 5 and Root ZX II had similar accuracy in determining working length of root canals. The ex vivo methodology for evaluation of the accuracy of ERCLMDs was validated when compared with the in vivo results.
authors.affiliation: Department of Restorative Dentistry, Endodontic Division, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: R M V
authors.initials: RM
authors.lastname: Soares
authors.forename: E J N L
authors.initials: EJ
authors.lastname: Silva
authors.forename: D R
authors.initials: DR
authors.lastname: Herrera
authors.forename: R L
authors.initials: RL
authors.lastname: Krebs
authors.forename: T S
authors.initials: TS
authors.lastname: Coutinho-Filho
mesh_terms: D004582:Electronics, Medical; D006801:Humans; D066298:In Vitro Techniques; D009811:Odontometry / Q000295:instrumentation*; D012390:Root Canal Therapy
keywords: accuracy; electronic root canal length measurement device; working length