Aim: To evaluate ex vivo the accuracy of the multifrequency electronic apex locator (EAL) Joypex 5 in primary molars.
Methods: Fourteen primary molars were selected for a total of 25 root canals. Working length measurements were performed by direct observation (DO), using a 15 K-file into the root canal until its tip was visible at the apical foramen and electronically using the EALs Joypex 5. Data were analysed statistically using the intraclass correlation coefficient (ICC). To assess whether a significant difference in accuracy of the electronic apex locator existed, the Student's t test was performed at 5% significance.
Results: No statistical difference was observed between the direct observation and the EAL measurement (p < 0.05). The ICC confirmed the agreement of different methods to measure canal length. The R(2) coefficient was close to 1, denoting a strong agreement between measures obtained with Joypex 5 and DO.
Conclusion: The multifrequency EALs Joypex 5 showed adequate accuracy in the root length determination of primary teeth.