[Direct Comparison of Working Length Determination by ProPex Electronic Apex Locator and Radiographic Method--an in Vitro Study].

The purpose of this study was to compare the accuracy of electronic and radiographical working length determination in extracted molars. Palatal root canals of twenty maxillary molars were used. Teeth were randomly divided into two groups. In case of the first group the working length was measured by apex locator (Propex, Dentsply-Maillefer), and in the second group it was measured with radiographic method (RVG, Trophy). The files, used for measuring the working length, were cemented into the teeth. The apical half of the root was ground, and the tips of the files visualised as well as the apical region of the root canal with the apical constriction. Standard digital photographs were taken from the prepared samples, and the distance between the tip of the file and the physiological foramen was measured. Two sample t test was used for statistical analysis. The physiological foramen was approached on average to 0.11 mm by the electronic method and to 0.58 mm by the radiological method. There was no significant difference in the measuring accuracy between the two methods (p=0.10). The electronic and radiological working length determination may prove to show an equivalent consistency.