A comparison between xeroradiographs and conventional radiographs as an aid in root canal therapy for maxillary molars

The purpose of this study was to compare the quality of images obtained with dental xeroradiography to that obtained with conventional dental radiography during performance of root canal therapy on maxillary molars. For each step requiring radiographic information during endodontic treatment of 12 maxillary molars, a conventional radiograph and a xeroradiograph were made. This produced four pairs of images for each tooth treated as follows: (1) preoperative, (2) initial files for length determination, (3) master cones fitted, and (4) completed obturation of the root canal systems. The same x-ray machine was used as the source of radiation for all exposures with a setting of 70 kVp and 15 mA and with near identical projection for each pair of images achieved through use of a modified film holder and a custom positioning occlusal index made for each patient. Exposure time for the radiographs was 60 impulses (1 impulse = 1/60 second) and for the xeroradiographs it was 42 impulses. Images of structures and items important in endodontic diagnosis and treatment were rated as unacceptable (0), poor (1), adequate (2), or optimal (3) by four independent evaluators. Analysis of data showed the following: images of bone trabeculae, periodontal ligament spaces, root morphology, root apices, and fine bony abnormalities were judged to be significantly better in the radiographs than in the xeroradiographs (p less than 0.01) whereas there were no significant differences in image quality of pulp chamber morphology, root canal morphology, metallic measuring instruments, or endodontic filling materials.