Tooth Distortion as a Function of Arch Form in Cone Beam Computed Tomography

The cone beam computed tomography enables conducting measurement of length and area in the space where it is impossible to conduct such measurement compared to panorama. The cone beam computed tomography also enables making three-dimensional diagnosis and establishing treatment plan. In this experiment, the cone beam computed tomography was used to analyze image distortion of anatomical structure whose location was different between panorama and reconstructed panoramic image. Multiplanar reformation image was obtained after radiography of mandibular dentition. Then, the axial image was examined to obtain cross-sectional images of teeth that ranged from the right second molar to the left second molar before diameter of crown was measured and compared. Based on the cross-section that was radiographed by using the cone beam computed tomography, comparison was made between reconstructed panorama and standard panorama. According to the results of comparison, diameter of crown was measured with a slight difference of around 0.03 mm between the cone beam computed tomography cross-sectional image and the reconstructed image. It was also found that panorama caused image distortion with the large error of around 0.95 mm. Based on these results, it was confirmed that the cone beam computed tomography panorama that was reconstructed in consideration of patient's anatomical structure showed less distortion than the existing panorama. It was also confirmed that depending on distance, there was decrease in reliability of measurement of anatomical structure whose location was different in the existing panoramic image. It is necessary to develop methods and various programs in the future to improve poor image information that is obtained from the cone beam computed tomography and panorama examination.