Image quality in panoramic radiography

Because of the increase in panoramic radiography it is important to know if image quality has improved with recent technical developments and if there are differences between the different machines that can justify the difference in price. Six conventional panoramic units and the two panoramic programs (dental and jaw panorama) of the Scanora (Soredex, Orion Corporation Ltd, Helsinki, Finland) multi-modal unit were compared by evaluating the radiographs for subjective image quality and estimating the number of additional intra-oral radiographs necessary for a comprehensive evaluation of the periapical and periodontal bone status. Patients ranging in age from 40 to 60 years with teeth in all four quadrants were selected at random and radiographed with each machine or program. Thirty matching radiographs were selected from our archives in order to evaluate one machine (Orthopantomograph 5, Siemens AG, Bensheim, Germany) which was no longer in use. Seven oral radiologists scored the image quality of between 34 and 36 of the 240 radiographs on a 4-point scale and recorded the additional radiographs needed. The results showed that the mean score for the Scanora dental panorama was significantly higher than mean scores for the other machines/programs for both the periapical and crestal bone. The mean scores for the conventional machines and the Scanora jaw panorama program were not significantly different from each other. The image quality of radiographs obtained with the Orthopantomograph 5 was similar to that attained with the more modern machines. The mean number of additional intra-oral radiographs was lowest for the Scanora dental panorama. We conclude that the Scanora dental panorama program provided the best subjective image quality.