An evaluation of image quality for the assessment of the marginal bone level in panoramic radiography. A comparison of radiographs from different dental clinics.

The diagnostic image quality of panoramic radiographs originating from different clinics was examined. Two samples of 98 and 100 radiographs, respectively, were from a department of oral radiology. The radiographs of one of these samples were checked using immediate subjective analysis of the image quality before inclusion in the study whereas the radiographs of the other sample were randomly selected. A third sample consisted of radiographs from 20 randomly selected dental clinics. The subjective overall image quality of the whole panoramic radiograph was classified as adequate, marginal or inadequate. The three observers also assessed the reason for inferior image quality. The overall image quality of the radiographs was better for the checked sample from the department of oral radiology compared to the sample form the 20 dental clinics. The main reason for unacceptable image quality of the radiographs was too low density and/or contrast irrespective of sample. Other faults were incorrect positioning of the patient but in the sample from the 20 clinics improper film handling was also frequent. We conclude that image quality in panoramic radiography can be improved. Improvement of the image quality is a prerequisite if panoramic radiography in the future is to replace the full-mouth examination.

Technical failures and some related clinical complications in extensive fixed prosthodontics. An epidemiological study of long-term clinical quality.

Three hundred and sixteen fixed partial dentures made in 1975-1976 by 112 general practitioners in Malmö, Sweden, were selected for a questionnaire study of the technical failure rates after 6-7 years. Cariologic, periodontal, endodontic, and esthetic complications were also identified, as were those appearing in the stomatognathic system. The total material consisted of three groups with an approximately equal number of reconstructions. One group consisted of fixed partial dentures with distal abutment teeth, another was formed of fixed prostheses with single cantilever pontic/pontics, and a third consisted of double cantilever pontics. Excluding the 26 reconstructions, which had been made for patients who died (24) or emigrated (2) during the observation period, data was obtained for 97% of the selected restorations. The results showed high rates of cariologic (18-31%), endodontic (5-23%), periodontal (7-12%), esthetic (10-16%), and technical (8-34%) complications. Differences were noted between the groups. For all types of technical failures (fractures and loss of retention) higher frequencies were related to the extent of cantilevering. Direct relationships were found between the technical failure rate and the time in service, the sum of all cantilever extension pontics in the reconstructions, and the state of the pulps of the distal abutments. No relationship was found between the technical failure rate and the status of the dentition in the opposing jaw. The clinical significance of the results obtained is discussed.

On intraoral potential- and polarization-measurements of metallic restorations. A methodological and time dependent clinical study.

A study was conducted to scrutinize the precision of a method for in vivo potential and polarization measurements. The variation with time of the magnitude of currents created at contacts between metallic dental restorations of varying age was also studied. The precision found indicates that the method allows for comparatively precise measurements of potentials to be taken. Studies of performed measurements of polarizations show that the precision of these measurements varies somewhat with contact conditions and the areas of restorations examined. The precision of the currents calculated was found sufficient for precise enough calculation to be made of the magnitude of currents created in the oral cavity. The study also shows a decrease with time of the magnitude of currents created at contact between metallic dental restorations of varying age.