摘要：OBJECTIVE: The aim of this study was to compare the accuracy of two electronic apex locator devices after root canal preparation at different sizes. MATERIALS AND METHOD: Fourteen extracted mandibular incisors were used in this study. Crowns were removed at the cementoenamel junction. The actual canal length was determined by introducing a size 10 K-file into the canal until the file tip became visible at the apical foramen and then subtracting0.5 mm from the measured length. The teeth were embedded in alginate model. Initial (pre-operative) root canal length measurements were performed by using Propex II and Root ZX mini electronic apex locators. Then, the root canals were prepared by using ProTaper rotary system to size F1. Working lengths were measured again by using the two electronic apex locators. Finally, the root canals were prepared to size F3 and the working lengths were measured once more by using the same devices. Differences between the actual working length values and the electronic apex locator values (initial values and values obtained after F1 and F3 preparation sizes) were calculated and compared statistically using t-test. Comparisons were done both between the two devices and within each device. RESULTS: No statisticall significant difference was found between and within the readings of the Propex II and Root ZX mini electronic apex locator devices for measurements performed at the different stages (p>0.01) CONCLUSION: Propex II and Root ZX Mini electronic apex locator devices exhibited comparable results at the beginning of the root canal treatment and at different preparation sizes.
