title: An in vitro evaluation of performance of two electronic root canal length measurement devices during retreatment of different obturating materials.
abstract: BACKGROUND
  The purpose of this in vitro evaluation was to study the accuracy of Root ZX and ProPex system during retreatment of canals obturated with different obturating materials (gutta-percha + zinc oxide-eugenol sealer, gutta-percha + AH plus sealer, and Resilon + Epiphany sealer).
  
  
  METHODS
  Sixty human mandibular premolar roots were instrumented with Rotary ProTaper until size F4 under copious irrigation. After instrumentation, actual working length was directly measured by using #15 FlexoFile. Electronic working length was taken with the help of Root ZX and ProPex. Teeth were divided into 3 groups and obturated by using lateral condensation of gutta-percha + zinc oxide-eugenol sealer (group I), gutta-percha + AH plus sealer (group II), and Resilon + Epiphany sealer (group III). After 7 days, the obturating materials were removed by using Gates-Glidden burs and K-files. A new electronic working length was taken. Original and post-treatment electronic working lengths were compared with actual working length. Accuracy of both electronic root canal length measurement devices was calculated for tolerance limits of +/-0.5 mm and +/-1.0 mm. Accuracy was compared by using chi(2) tests, and difference between actual working length and original and post-treatment electronic working lengths was compared by using Student t test.
  
  
  RESULTS
  The accuracy of electronic root canal length measurement devices before root canal obturation was 83.3% and 93.3% for Root ZX and ProPex, respectively, for a tolerance limit of +/-0.5 mm and 100% for a tolerance limit of +/-1.0 mm. There was no statistically significant effect of different obturating materials tested in this study on the accuracy of Root ZX and ProPex for tolerance limits of +/-0.5 mm and +/-1.0 mm. Student t test revealed insignificant differences between the mean of actual working length and original and post-treatment electronic working lengths.
  
  
  CONCLUSIONS
  Root ZX and ProPex can be a useful adjunct with a high accuracy rate during root canal preparation and retreatment.
authors: Department of Dental Surgery, Safdarjung Hospital, New Delhi, India. drvivekaggarwal@gmail.com
authors: Vivek
authors: V
authors: Aggarwal
authors: Mamta
authors: M
authors: Singla
authors: Debipada
authors: D
authors: Kabi
mesh_terms: D001641:Bicuspid / Q000033:anatomy & histology / Q000601:surgery; D016009:Chi-Square Distribution; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000601:surgery; D017097:Electric Impedance; D004853:Epoxy Resins / Q000737:chemistry; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D008334:Mandible; D009811:Odontometry / Q000295:instrumentation*; D015203:Reproducibility of Results; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation*; D012680:Sensitivity and Specificity; D019227:Tooth Apex / Q000033:anatomy & histology; D014092:Tooth Root / Q000033:anatomy & histology* / Q000601:surgery; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry
chemical_list: D004853:Epoxy Resins; D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; C486893:epiphany sealer; C534916:epoxy resin-based root canal sealer; C486892:resilon sealer; D006171:Gutta-Percha