Panoramic radiography in the assessment of the marginal bone level.

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.