Prospective study on the reproducibility of cephalometric landmarks on conventional and digital lateral headfilms

The introduction of digital X-ray techniques offered a variety of new possibilities for digital image enhancement and exposure reduction. In order to compare the reproducibility of cephalometric landmarks on conventional and digital lateral headfilms 100 digital and 100 conventional lateral headfilms of patients attending our clinic were randomly selected. The digital cephalograms were obtained using storage phosphor plates in standard X-ray cassettes. All X-rays had been taken at 77 kV. For the digital images the mAs settings for conventional images minus 4 mAs were used. Two orthodontists traced each X-ray twice (21 reference points) at an interval of at least 1 week. The tracings were superimposed and the distances between the tracings of identical reference points were registered. The average reproducibility of cephalometric landmarks was significantly higher on the digitally obtained images, despite a reduction of radiation exposure of 23.7% in the digital images.