Use of the direct magnification technique in dental radiology

OBJECTIVE To investigate the potential use of the direct magnification (DIMA) technique in dental radiology. METHODS Radiographs of anatomical specimens and extracted teeth were prepared under clinical conditions using a microfocus (8 and 16 microns focal diameter) X-ray tube. Entrance dose was measured using an ionization chamber. Image quality was assessed in a single-blind test of pairs of images of extracted teeth with and without caries by ten observers. RESULTS At 7.3 x magnification the values for exposure time and entrance dose were comparable with those for conventional intraoral radiography, 0.1 and 0.25 s and 1.5 and 2.9 mSv respectively. Diagnostic accuracy using the DIMA images was significantly (P < 0.0001) better compared with dental radiographs. CONCLUSION DIMA images with significantly enhanced diagnostic accuracy can be obtained at comparable exposure times and entrance doses to conventional intraoral radiographs.