comparison between the accuracy of digital and conventional radiographies for evaluation of the curved canals length

introduction proper cleaning and shaping of the root canal system is one of the most important aspects of endodontic therapy. to estimate the canal length before instrumentation in endodontic treatment, traditionally, conventional radiographic techniques and, recently, direct digital radiography (ddr) are applied. the application of computer technology in radiography has allowed less exposure time for image acquisition, better storage and retrieval, and transmission to remote sites in a digital format, elimination of processing, and a considerable time saving. the purpose of this study was to compare the accuracy of ddr and conventional radiography in determination of working lengths of curved canals in first mandibular molars. methods forty extracted human first mandibular molars with root curvature were selected. samples were divided into two groups: with root curvatures less and more than 25°. the samples were mounted in plaster blocks and their canal lengths were estimated by using ddr and conventional radiographs. regression analysis, correlation coefficient, and t test were used for statistical analysis. results in spite of the greater accuracy of conventional radiography in canals with curvature 25°, the differences were not statistically significant. discussion both conventional radiographs and ddr can be used to determine working length during endodontic therapy. key words digital imaging, conventional radiography, working length, root curvature.