Precision in Cephalometric Measurements: Comparison of Cone Beam CT Lateral Cephalogram and Direct Digital Lateral Cephalogram

Now, direct digital lateral cephalogram (DD-LC) is wide spread and routinely used in orthodontic practice. Recently, cone beam computed tomography (CBCT) technology is widely used in orthodontics to acquire 3D information. Many devices are new capable of a large field of view imaging of the skull to include most anthropometric landmarks used in cephalometric analysis. In current clinical practice, the CBCT DICOM image datasets can be reconstructed to generate a 2D CBCT- lateral cephalograms so that conventional measurements can be made and compared with existing 2-D norms. The advantages of using CBCT lateral cephalograms (CBCT-LC) include the ability to digitally reorient the head position after the initial scan in cases in which the patient did not undergo scanning with the proper head position and the ability to enhance the image quality by virtually sculpting away extraneous superimposing skeletal structures that are not relevant to the lateral cephalometric measurement process (for example, vertebrae). All the previous study related to CBCT cephalometry were on ex vivo human skulls, and they may have some potential limitations when using 3D images derived from CBCT data: unable to simulate soft tissue effects of attenuation on image quality which may have allowed easier identification of landmarks. However, there is a lack of data regarding the reliability and precision of measurements obtained from CBCT constructed cephalograms of orthodontic patients. We hypothesize that the precision of measurements obtained from CBCT LC is similar to the precision of measurements obtained from DD-LC using specific orthodontic software and analysis. Keywords: Measurement Precision, Cone Beam Computed Tomography Lateral Cephalogram, Direct Digital Lateral Cephalogram, Reconstructed Cephalogram