Comparison of digital dental X-ray systems with self-developing film and manual processing for endodontic file length determination.

Human skulls were sectioned into 15 sextants. Teeth were then removed and 45 canals were instrumented to their apical foramina. Endodontic files were glued in place at random distances from the apical foramina. Image geometry was maintained by a custom mounting jig. Images were captured with self-developing film, manually processed D-speed film, and a digital radiographic system (Dexis). Digital images were read on a conventional color monitor (cathode ray tube) and a laptop screen (active-matrix liquid crystal display). Fifteen dentists measured the distance from the file tip to the apical foramen of the tooth. Results showed that the measurement error was significantly less for the digital images than for the film-based images. It is likely that these statistical differences may not be of great clinical significance because the digital images could be measured in increments < 0.25 mm.