Quality of Film-based and Digital Panoramic Radiographs

Objectives: To compare the image quality of panoramic radiographs obtained with storage phosphor plate and screen/film systems. Methods: In 60 patients panoramic radiographs were taken both with film (Lanex medium (Eastman-Kodak, USA)/Curix Ortho HT-G (Agfa-Gevaert NV, Belgium)) and image plates (30 with DenOptix (Dentsply/Gendex, USA) and 30 with Digora PCT (Soredex, Finland)). The digital images were displayed as 8 bit images with the resolution 300 dpi on a Nokia 445Xi 19" screen. The film images were placed on a light-box adjacent to the screen. By means of visual grading analysis ten observers evaluated the diagnostic image quality of the lower and anterior border of the maxillary sinus, the periodontal bone level, the peri-apical bone structures, the trabecular bone, the mandibular canal and the mental foramen. The structures were scored as being visualized much better (5), better (4), equal (3), worse (2) or much worse (1) in the digital images than in the film images. The mean number of patients given the different scores was calculated. Statistical methods used were Wilcoxon sign rank test and Mann Whitney test. Results: In the majority of the patients diagnostic image quality in film and digital radiographs was deemed equal. Statistically there was a small but significant (p<0.0001) difference. The difference between the two image plate systems was not statistically significant (p>0.17). Conclusions: Digital panoramic radiographs obtained with image plates are equivalent to film-based ones for most purposes. This study was supported by grants from Sigge Perssons & Alice Nybergs Stiftelse för Odontologisk Forskning and Svenska Tandläkare-Sällskapets vetenskapliga fonder.