Panoramic radiography in dental diagnostics

Panoramic radiography was studied with the aim to answer some questions about technical and diagnostic properties regarding dental diagnostics. A unit with an intraoral X-ray tube was studied regarding radiation beam area, absorbed doses, and image quality for various screen-film combinations. The beam area for lateral views was wider than optimal and the contact dose high. Modifications of shielding cylinders would reduce both radiation beam and contact dose. One screen-film combination was most sensitive and produced radiographs with best subjectively perceived image quality. Agreement between panoramic (rotational and intraoral X-ray tube techniques) and intraoral radiography in diagnosis of periapical pathology, assessment of marginal bone height, and caries diagnosis was evaluated in 400 patients. Average agreement between panoramic and intraoral radiographs in periapical diagnosis was 55% for the rotational and 46% for the intraoral tube technique. Agreement in marginal bone height was 55% and 49%, respectively and in caries diagnosis 34% and 46%. Radiographs from 40 patients were used to evaluate a procedure starting with rotational panoramic radiography followed by intraoral radiographs considered necessary to achieve a comprehensive examination of teeth and surrounding bone. The number of intraoral radiographs, information loss, and monetary costs with this procedure were evaluated. Mean number of adjunct intraoral radiographs was 5.1 per patient whilst 8.5 should have been chosen to satisfy a "gold standard" used. Monetary costs were similar for an optimal combination of panoramic and intraoral radiography as for a survey with 20 intraoral images Sensitivity for a combination of radiographs was 80-96% in periapical diagnosis and marginal bone loss assessment, and 42-96% in caries diagnosis. Specificity was 95-97% for periapical and caries diagnosis and 50-92% for marginal bone loss. Radiographs from six conventional units and two programs ("dental" and "jaw" panorama) of a new multi-modal unit were compared in diagnostic quality of periapical and crestal bone areas. Number of adjunct intraoral radiographs to achieve a comprehensive evaluation of periapical and marginal bone was estimated. Quality of the "dental" panorama was significantly better than that of other machines/programs. There were no significant differences between images obtained with conventional units and the "jaw" panorama. Number of adjunct intraoral radiographs was lowest for the "dental" panorama. Quality obtained with an old unit was similar to that from modern machines. Rotational and intraoral X-ray tube panoramic radiography perform equally well. Agreement between panoramic and intraoral radiography is not sufficient for panoramic radiography to be used alone to diagnose periapical lesions, marginal bone loss and caries. It is possible to perform a full-mouth survey with a combination of panoramic and intraoral radiography but when limited regions need to be examined intraoral radiography is the method of choice.