Precision of measurements on conventional negative 'bones white' and inverted greyscale 'bones black' digital lateral cephalograms

The objective of this study was to determine whether the accuracy of measurement data from inverted greyscale digital cephalometric radiographs equals that obtained from conventional negative digital cephalometric radiographs. Fifty-five consecutively lateral cephalometric radiographs from a university orthodontic clinic obtained for treatment planning were used for this study. A 5 MB conventional negative 'bones white' and inverted greyscale 'bones black' TIFF digital image of each radiograph was produced. These were allocated a unique identifier and were analysed in random order by one clinician. Eighteen cephalometric landmarks were digitized using the Opal 2.1 package and the angles were calculated. The angular measurements were compared using two-sample t-tests (P < 0.05).

The angular measurements from the conventional negative bones white and inverted greyscale bones black lateral cephalometric radiographs were neither statistically significantly different nor clinically different from each other. Therefore, measurements derived from conventional negative bones white and inverted greyscale bones black lateral cephalometric radiographs have a similar level of precision.