ABSTRACT
PURPOSE: This study aims to investigate if 2D analysis method is applicable to analysis of CBCT by comparing measuring points of CBCT with those of Adjusted 2D Lateral Cephalogram (Adj-Ceph) with magnification adjusted to 100% and finding out at which landmarks the difference in position appear. MATERIALS AND METHODS: CBCT data and Adj-Ceph (100% magnification) data from 50 adult patients have been extracted as research objects, and the horizontal (Y axis) and vertical (Z axis) coordinates of landmarks were compared. Landmarks have been categorized into 4 groups by the position and whether they are bilaterally overlapped. Paired t-test was used to compare differences between Adj-Ceph and CBCT. RESULTS: Significant difference was found at 11 landmarks including Group B (S, Ar, Ba, PNS), Group C (Po, Or, Hinge axis, Go) and Group D (U1RP, U6CP, L6CP) in the horizontal (Y) axis while all the landmarks in vertical (Z) axis showed significant difference (P<.05). As a result of landmark difference analysis, a meaningful difference with more than 1 mm at 13 landmarks were indentifed in the horizontal axis. In the vertical axis, significant difference over 1 mm was detected from every landmark except Sella. CONCLUSION: Using the conventional lateral cephalometric measurements on CBCT is insufficient. A new 3D analysis or a modified 2D analysis adjusted on 19 landmarks of the vertical axis and 13 of the horizontal axis are needed when implementing CBCT diagnosis.