OBJECTIVES: The aim of this study was to evaluate the precision of the
cephalometric analysis using the
orthodontic software Orthometric((R)) in two modes: fully automatic without any help by the user and semiautomatic with manual determination of all cephalometric landmarks. METHODS: From 100 indirectly digitally produced cephalographs, 72 were chosen
randomly. On each one of these, three methods were applied on 12 decision-relevant cephalometric angles according to Hasund/Segner: (1)
hand drawing on a transparent sheet over the cephalographic film; (2) software semiautomatically with manual correction on the screen; and (3) fully automatically. The hand-based method (1) is well established as a
quality standard and reference. The angle measurement results of this method were compared with those of the semiautomatic and the fully automatic method by calculation of the
mean absolute differences. Additionally, five
randomly chosen cephalographs were evaluated ten times using all three methods for
statistical evaluation of
reproducibility. RESULTS: At tenfold evaluation of five cephalographs, the
standard deviations of the angles were between 0.05 degrees and 0.8 degrees . These results were similar using all three methods. All three methods had similar
reproducibility. At evaluation of 72 cephalographs, the
mean absolute angle differences between the hand-based (1) and semiautomatic (2) methods were below 2 degrees and so within the allowed tolerance limit, except for the nasolabial angle. In contrast to this, all
mean absolute angle differences between the (1) hand-based and (3) fully automatic methods exceeded 2 degrees , and with this the tolerance limit allowed by literature. CONCLUSIONS: The fully automatic determination of the cephalometric landmarks has
led to relevant errors up to now, so that it is mandatory to check all automatically set landmarks and to correct them if required. In the case of the semiautomatic method, all relevant angles can be determined with the same reliability as
hand drawing.
