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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.

Panoramic, bitewing and periapical radiography and probing for measurement of the marginal bone level were compared. Altogether 237 sites of 23 patients were examined. Radiographs were taken with a splint containing steel balls to allow calculation of the enlargement of the radiographs. Probing was done before and during flap surgery using the same splint. The open bone measurement represented the true value. All radiographs were assessed by 5 observers. The mean enlargement of panoramic radiography was 27% in the upper and 26% in the lower arch. For bitewing and periapical radiography, it was 8% in the upper and 4-5% in the lower arch. All methods underestimated the bone loss. Probing bone level before surgery was most accurate, deviating at most 5% from the true value. Periapical radiography was more accurate than panoramic and bitewing radiography (p less than 0.001). Panoramic radiography presented a slightly lower mean accuracy than bitewing radiography (p less than 0.05). The underestimation of the bone loss ranged from 13 to 32% in orthopantomograms, 11-23% in bitewing and 9-20% in periapical radiographs. The interobserver variation of the radiographic methods was substantial.

The radiation dosage for the Orthopantomograph model OP5 was measured using two different sizes of collimators. The concordance between and accuracy of panoramic radiography and periapical and bitewing radiography was examined regarding assessment of the marginal bone level. The measurability of panoramic and periapical and bitewing radiographs was compared, as was the image quality of panoramic radiographs from one selected sample and two random samples. The energy imparted was 0.4-0.8 mJ for one panoramic radiograph. The use of the narrow collimator reduced the dosage by about one-third. The concordance between panoramic and intraoral radiography was high. In some anatomical regions, the concordance was as high as the intraobserver agreement for one and the same technique. The concordance was lower in sites with severe bone loss, however. Sounding was very accurate for the measurement of the marginal bone loss. Of the radiographic techniques, periapical radiography was most accurate. The observer performance for linear measurements of bone loss varied substantially and systematically among five observers. The measurability in the upper arch was the same in panoramic and periapical radiography. In the lower arch, the measurability of periapical radiography was better. The image quality of panoramic radiography influenced the measurability. The image quality of panoramic radiographs from random samples was inferior to that of the selected sample. It was concluded that, for the assessment of the marginal bone level, the panoramic radiograph should be the radiographic examination of choice, if increased image quality is achieved.