The effects of beam quality and optical density on image quality in dental radiography

The literature relating to the choice of beam quality in dental radiography is reviewed. Twenty observers were asked to select radiographs of a test object at different beam qualities and densities. The same observers were asked to identify numbers of circular areas of small density differences in zones of high and low density. Subjectively, the observers favored radiographs produced with lower beam energies; 90 kVp aluminum filtration and 3.5 mm was least popular, and 70 kVp with 2.5 mm aluminum was most popular. Objectively, there was little difference in the success of identification between the beams of different energies. Masking of radiographs improved success apart from the low density zones in less exposed radiographs. Little evidence has been found within the range investigated for selecting one beam quality over another, other than subjective preference. However, low beam energies should be avoided because of reduced emulsion sensitivity.