Aim: The present study compared the efficacy of digital and conventional radiology for root-canal length measurement. Methodology: Seventy extracted teeth with preserved roots were used. Root-canal length measurements were completed with K-Flexofiles (numbers 08, 10 and 15) with conventional and digital radiography using two systems (radiovisiography and photostimulate storage phosphor). All films and sensors were exposed at projections of 0° and 20° to the mesial. The images obtained were evaluated with and without magnification, and analysed using the Cohen's kappa test. The accuracy of the three systems to determine the root-canal length were evaluated by measuring the distance from the tip of the file to the apex. Results: Most of the values corresponding with the apex occurred with conventional radiology. The digital systems yielded negative values that improved with a size 15 file. The agreement between the two digital systems was the best with size 15 file using 0° projection (66.7%). Conclusions: Conventional radiology remains the technique of choice in determining the root-canal length; the digital techniques yielded good results for size 15 file.
