Accuracy of Digital Panoramic Radiographs: Monitor-displayed Images Compared with Prints on Glossy Paper and Transparent Film

Objectives: The aim of this study was to compare the accuracy of three modalities of digital panoramic radiographs: monitor-displayed images and printed copies on glossy paper and on blue transparent film for diagnosis of mandibular third molars. Methods: 164 fully or semi-impacted third molars were available for examination. Images of these molars were enhanced by an observer trained in optimizing digital images and thereafter printed using the ink-jet printer, Kodak 1200 Distributed Medical Imager (Kodak Digital Science) on two hardcopies: blue transparent film (Kodak DMI medical film) and glossy paper (Kodak ink-jet paper). The images were obtained by two digital panoramic systems Digora PCT (Soredex, Finland) and Orthophos Plus (Sirona, Germany). Position and morphology of third molars were assessed by four observers on the three modalities: monitor-displayed, glossy paper and transparent film and compared with surgeons’ findings at the time of operation (“gold standard”). The agreement between each observer’s scores and the gold standard was calculated for each of the modalities. Differences between the three modalities were analyzed by McNemar’s test for paired samples. The level of statistical significance was set at P<0.05. Results: Few differences were found in diagnostic accuracy between the modalities, but inexperience in using digital image enhancement could have influenced some of the observers as they for a few diagnostic items were more accurate when assessing the hardcopies than the monitor-displayed images. Conclusion: Printed images on glossy paper and blue transparent film are as accurate as the original monitor-displayed panoramic radiographic images from the Digora and Orthophos Plus systems for assessment of position and morphology of mandibular third molars.