AIM: To test an electrical device for determining root canal length in primary teeth in vitro, and to compare it with the radiographic length measurement. METHODOLOGY: 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. CONCLUSION: 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.
AIM: To test an electrical device for determining root canal length in primary teeth in vitro, and to compare it with the radiographic length measurement. METHODOLOGY: 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. CONCLUSION: 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.