Effect of ambient light and bit depth of digital radiograph on observer performance in determination of endodontic file positioning

ObjectivesTo examine the effects of the luminance and bit depth of digital image on observer performance for determination of endodontic file positioning.Study designUsing extracted premolar teeth, no. 08 K-file was placed into the canal and positioned so that the tip was either flush or 1 mm short of the radiologic root apex. The samples were imaged with both conventional and digital radiographs at 8 and 12 bits. Eleven observers read the images under dark and bright condition, and receiver operating characteristics analysis was performed. Additionally, the interpreting time was measured.ResultsThe 12-bit images showed similar observer performance compared with conventional images, and better than the 8-bit images. The interpretation time for bright condition and 8-bit images was longer than for dark condition and 12-bit images.ConclusionTwelve-bit digital images were preferred to 8-bit for accurate determination of endodontic file position.