Objective: The aim of this study was to evaluate the accuracy of electronic apex locator (Root ZX) in primary teeth with and without apical root resorption in vivo.
Study design: The electronic working length was determined in 28 primary teeth (A total of 46 primary molar root canals with 24 roots without resorption and 22 roots with resorption) from twenty-eight healthy children using Root ZX. The teeth were then extracted. The actual length of each root was measured placing a K-File until the tip was visible at the apical foramen or the apical resorption level and approved with digital microscopic evaluation under 20x magnification and then withdrawn 1 mm. The distances from the file tip to the base of the rubber stop were measured and compared with the measurement obtained from apex locator. The data were evaluated with t test using standard statistical software (SPSS 13.0). The critical value of statistical significance was 5%.
Results: For root canals without resorption, the accuracy of Root ZX was 79.16% and 95.82% within +/- 0.5 and +/- 1 mm, respectively. For root canals with resorption, the accuracy of Root ZX was 63.63% and 86.35% within +/- 0.5 and +/- 1 mm, respectively. No statistically significant differences were detect between the electronically determined lengths and the actual lengths regardless of whether or not resorption.
Conclusion: Using a Root ZX Electronic Apex Locator in primary teeth with or without resorption is recommended for the determination of working length.