Positioning errors in panoramic images in general dentistry in Sörmland County, Sweden.

The purpose of this study was to evaluate the frequency and severity of positioning errors in panoramic radiography in general dentistry. A total of 1904 digital panoramic radiographs, taken by the Public Dental Service in the county of Sörmland, Sweden, were analysed retrospectively. The study population consisted of all patients who underwent a panoramic examination during the year 2011. One experienced oral radiologist evaluated all radiographs for 10 common errors. Of the 1904 radiographs examined, 79 per cent had errors. The number of errors varied between 1-4 errors per image. No errors were found in 404 images (21%). Fifty-five images (3%) had severe errors, which made it impossible to make correct diagnostics. The most common error was the tongue not being in contact with the hard palate during exposure. However, this did not greatly affect the diagnostic usefulness of the image due to the ability to enhance the image.The patient's head was tilted too far upwards in 23 per cent of the images and the patient's head was rotated during exposure in 15 per cent. The least common error was due to patient movement during exposure (1%). Panoramic radiographs taken in general dental clinics in a Swedish county show several errors. Proper positioning of the patient is necessary to achieve panoramic images with good image quality. Some of the errors could be adjusted with the digital technique used.This allowed assessment of the images, which reduces radiation dose by avoiding retakes.