Intra-oral computed radiography—an in vitro evaluation

Objectives: 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. Methods: 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. Results: 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). Conclusions: 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.