Determining the Degree of Identification Differences in Anatomical Landmarks by Digital Cephalometric Radiography and Conventional Radiographic Technique Using Manual Tracing of Human Skulls

Background and Digital radiography has led to many improvements in radiology. Despite many advantages there are different ideas in determining anatomical landmarks which results in some errors in cephalometric analyses. The aim of this study was to determine the degree of identification differences of anatomical landmarks by conventional and digital lateral cephalometric techniques using manual tracing of human skulls. This descriptive-analytical study was conducted in 17 cases of human skulls in which metal radiopaque markers were attached to 9 landmarks as follows: N, S, ANS, PNS, A, B, Pog, the most inferior point of lower mandibular border, and Go. Conventional and digital lateral cephalograms were obtained from each skull with and without markers. The two cephalograms without markers were traced for landmarks by three orthodontists. Any difference between these landmarks and those of cephalograms with markers, were recorded and analyzed by student t-test. The level of differences in S point was not statistically significant along both x and y coordinates. The measurement differences for the ANS and PNS points obtained by both radiographic methods were significant along the x coordinate but not significant along the y coordinate. Also, the measurement differences for the most inferior point of lower mandibular border, A, B, and Go points along both x and y coordinates were observed to be statistically significant. The measurement difference obtained for the Pog point was significant along the y coordinate and non-significant along the x coordinate. The difference in landmark identification between the two digital and conventional lateral cephalometric techniques was statistically significant for some points on both dimensions, however, the difference was not clinically significant.