Comparison of linear measurements on CBCT and digital postero-anterior cephalometric radiographs using human dry skull

Cephalometric images have limitations in the evaluation of measurements in three dimensions of space. In recent years، technological advances have made it possible to acquire 3D data on patients. This study sought to compare the accuracy of linear measurements made on digital postero-anterior cephalograms and CBCT images data with those made directly on dry skulls. In this random cross-sectional descriptive-analytical study 5 anatomic landmarks were determined on 5 dry human skulls. Direct measurements on the skulls were made with a digital caliper. Then، digital postero-anterior CBCT radiographs and CBCT images were taken and measurements were made using the relevant software programs. SPSS 11. 5 was used for the data analysis. ICC (intraclass correlation coefficients) test and the mean percentage differences were analyzed with Wilcoxon test (α=0. 05). Comparison of mean percentage differences showed significant differences between measurements made on digital postero-anterior cephalograms and dry skulls on one hand and those made on CBCT images (p value = 0. 001). The mean ICC was 0. 92 for CBCT technique and 0. 28 for digital lateral cephalometry technique. Under the limitations of the present study، direct measurements on dry skull were very close to measurements on CBCT images compared to those on digital postero-anterior lateral cephalograms. The accuracy of CBCT technique was much higher than digital postero-anterior lateral cephalometry technique.