Intra-oral computed radiography--an in vitro evaluation

The aims of this study were to compare the intra-oral radiographic images produced by computed radiography (Digora, Soredex, Helsinki, Finland) with conventional E-speed periapical films, in terms of image quality, radiation dosage and diagnostic value.

The physical measurement of image quality was conducted with a test grating. Radiation dosage was measured with an X-ray test device. Radiographic imagings were standardized using the left first permanent molar tooth of a dry human skull. The exposure timings ranged from 0.02 s to 2.32 s. Five dental surgeons rated the quality of the images produced by both systems. All raters were blind to the order of test.

The physical measurements of the new imaging plates revealed comparable results in terms of contrast differentiation. The resolution power, however, was slightly inferior: 5 lines/mm compared to 6 lines/mm for the E-speed films. Digital images were consistently scored as diagnostically acceptable throughout the exposure timings, while those for E-speed films range from 0.38 s to 1.8 s (P < 0.01).

The new imaging plate gave favourable results in terms of contrast differentiation. The resolution power, however, was slightly inferior to that with the E-speed film. Digital images of diagnostic quality were obtained even at 53% reduction of radiation compared to E-speed films.