The accuracy of the Neosono Ultima EZ apex locator using files of different alloys: an in vitro study.

The purpose of this study was to compare the precision of one of the new generation of root canal measuring devices, Neosono Ultima EZ, while using files manufactured of different alloys. Fifty-four root canals of extracted teeth were chosen. They were placed in special tubes with roots immersed in 2 percent agar with phosphate buffered saline. The device was used to locate the apex of each canal in wet conditions at the zero digital reading, first using a stainless steel file and then using a nickel-titanium file. These values were compared to the actual lengths obtained by measuring the distance of the coronal reference point to the apical opening with a size 10 file minus 0.5 mm. The accuracy of the device was 94 percent with nickel-titanium files and 91 percent with stainless steel. No significant difference was noted between the results for either file. The accuracy of the Neosono Ultima EZ in wet conditions exceeded 90 percent regardless of the alloy used.