An evaluation of root ZX and elements diagnostic apex locators.

The purpose of this study was to compare the accuracy of the Root ZX and Elements Diagnostic electronic apex locators under clinical conditions. Thirty-six teeth planned for extraction were used. Each tooth was decoronated, coronally flared with Orifice Shapers, and irrigated with 2.6% sodium hypochlorite. Working lengths were measured with K-files using both electronic apex locators. The files were cemented at the last measured working length and the teeth were extracted. The apical 4-mm of each canal were exposed and photographed under 15x and 30x magnification. Images of each apex were projected and the distance from the file tip to the minor diameter was determined. The mean distances from the file tip to the minor diameter were 0.346 mm for the Elements Diagnostic and 0.410-mm for the Root ZX beyond the minor constriction. In locating the minor constriction the Root ZX was accurate 75% of the time to +/-0.5 mm, 83.3% +/-0.75 mm, and 88.9% to +/-1 mm. The Elements Diagnostic was accurate 75% of the time to +/-0.5 mm, 88.9% to +/-0.75 mm, and 91.7% to +/-1 mm. There was no statistically significant difference between the accuracy of the two electronic apex locators in locating the minor diameter (p < 0.05).