Comparison of linear measurement accuracy on cone-beam computed tomography images and digital lateral cephalometric radiographs

Two-dimensional (2D) imaging has limitations in the evaluation of three-dimensional (3D) structures. In recent years، it has become possible to acquire 3D data of patients. This study sought to evaluate the accuracy of linear measurements of the skull made by cone-beam computed tomography (CBCT) technique and digital lateral cephalometry by two newly introduced Galileos and Planmeca machines. In this random descriptive/cross-sectional study، seven anatomical landmarks were determined on seven dry human skulls. Direct measurements on the skulls were made with a digital caliper. Then digital cephalometric radiographs and CBCT radiographs were taken. SPSS Ver. 11. 5 software was used for the data analysis. ICC (Intraclass Correlations Coefficients) test and mean percentage differences was calculated. The mean percentage differences between CBCT technique measurements and those made on dry skulls were less than 1 mm، less than 2 mm and 3 mm in 42%، 42% and 12% of variables. These mean differences between measurements lateral cephalometric images and those on dry skulls were less than 5 mm in 42% of cases and 10‒16 mm in the remaining 42%. The mean ICC values were more valuable in the CBCT technique than those in the digital lateral cephalometry technique. The accuracy of CBCT was much higher than digital lateral cephalometry. No directional magnification or minifying was observed I the CBCT technique.