ENDODONTIC MEASUREMENTS IN DIGITAL RADIOGRAPHS ACQUIRED BY A PHOTOSTIMULABLE, STORAGE PHOSPHOR SYSTEM

Digora(R) is a newly developed digital system for intraoral radiograph y utilizing photostimulable storage phosphor image plates. The aim was to test the quality of the system in respect to the visibility of end odontic files and root apices at different exposures. In teeth from fi ve dry mandibular jaw sections, Hedstrom files no. 15 were placed with the file rip al varying distances from the apex. The specimens were c overed with soft tissue equivalent material and placed behind a 2-cm t hick polymethyl methacrylale cylinder filled with aler. Distance from focus to image plate was 30 cm. Exposures were made at 60 kV and 7 mA at timer settings from 16 ms to 1000 ms in 50% increments. All images were viewed from the monitor by each of 8 observers allowed to use ava ilable contrast enhancement facilities to obtain subjectively good ima ge quality. Utilizing built-in measurement functions, distances from f ile lip and root apex, respectively, to a reference line were measured in 0.1 mm. For measurements between file tip and reference line, and root apex and reference line, there was no statistically significant d ifference between measurements made at the lowest exposure, compared t o the second lowest exposure bur there was a statistically significant difference compared to the 5 highest. Measurements at the second lowe st exposure were not significantly differ ent from those obtained at t he 5 highest exposures. Interobserver variability expressed as standar d deviation between observers showed the largest value for measurement s obtained at the lowest exposure. The mean observed distances between the tip of the file and the root apex were calculated and showed no s tatistically significant differences between different exposures. We c oncluded that the Digora intraoral image plate system provided reliabl e endodontic measurements even at very low exposures.