Effects of technical parameters on image perception using two types of dental radiographs

In radiology a sufficient diagnostic accuracy must be obtained with a minimal radiation dosage to which the patients are exposed. In-vitro studies designed to evaluate the influence of technical parameters on the quality of images on Kodak Ektaspeed and Kodak Ultra-Speed dental radiographs are presented. The following series of experiments were performed: 1. Evaluation of the Minray dc, Soredex and Oralix 65, Philips X-ray machines. 2. Comparison between two different Oralix 65 machines. 3. Evaluation of automatic and manual film processing as well as film-focus distances of 30 cm and 39 cm. 4. Evaluation of pairs of radiographs and their subtraction images obtained from different film and X-ray machine combinations. A dried mandible with and without bone splits within the central X-ray beam area on the alveolar crest between the teeth 46 and 47 served as object for the standardized images. A blind comparison of the series of images was performed by 3 certified periodontists. Irrespective of the film type used the highest rankings were given to the Oralix 65 X-ray machine, when the films were exposed at 39 cm from the focus and the automatic processing mode was used. X-ray images with good anatomical and technical details may be obtained on Ektaspeed and Ultra-Speed films. However, preference must be given to Ektaspeed films because of the possibility of reducing the radiation exposure.