title: Electronic determination of root canal length in primary teeth with and without root resorption.
abstract: OBJECTIVE
  To test an electrical device for determining root canal length in primary teeth in vitro, and to compare it with the radiographic length measurement.
  
  
  METHODS
  Two examiners determined the root canal length of 24 extracted maxillary primary incisors (12 with visible root resorption and 12 without) using an electrical root canal meter (Tri Auto ZX, Morita, Dietzenbach, Germany). The instrument was left in the root canal after the second examination and a radiograph was taken. The whole tooth was cleared by immersion in methylsalicylate and subsequently photographed. Both radiographs and photographs of cleared teeth were measured and compared with the electronic measurements.
  
  
  RESULTS
  The evaluation of the radiographs showed a mean distance between the instrument tips and apices of 0.60 (+/- 0.41) mm; evaluation of the cleared teeth showed an equivalent distance of 0.62 (+/- 0.40) mm. The mean distance between instrument tip and acceptable working length (determined with the clearing method) was 0.26 (+/- 0.24) mm in teeth without resorption and 0.29 (+/- 0.30) mm in teeth with resorption.
  
  
  CONCLUSIONS
  The presence of resorption in primary teeth did not affect the accuracy of electrical measurement of root canal length in vitro. The application of this method in primary teeth should be evaluated further.
authors.affiliation: Poliklinik für Zahnerhaltungskunde, Ruprecht-Karls-University, Heidelberg, Germany .
authors.forename: J
authors.initials: J
authors.lastname: Mente
authors.forename: J
authors.initials: J
authors.lastname: Seidel
authors.forename: W
authors.initials: W
authors.lastname: Buchalla
authors.forename: M J
authors.initials: MJ
authors.lastname: Koch
mesh_terms: D016001:Confidence Intervals; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D004553:Electric Conductivity; D004582:Electronics, Medical / Q000295:instrumentation*; D004867:Equipment Design; D005404:Fixatives; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007180:Incisor / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D015588:Observer Variation; D009811:Odontometry / Q000295:instrumentation; D010781:Photography; D011859:Radiography; D015203:Reproducibility of Results; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000473:pathology*; D012459:Salicylates; D013223:Statistics as Topic; D013499:Surface Properties; D019227:Tooth Apex / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014094:Tooth, Deciduous / Q000033:anatomy & histology* / Q000000981:diagnostic imaging
chemical_list: D005404:Fixatives; D012459:Salicylates; C033069:methyl salicylate