Background and purpose: Cone beam computed tomography （CBCT） is an imaging modality that is widely used in clinical practice. It allows physicians to obtain similar images to panoramic radiography. However, to the best of our knowledge, few studies have evaluated images, such as panoramic photographs, that have been reconstructed using CBCT （CBCT panoramic images）. The purpose of this study was to evaluate and compare CBCT panoramic images of the teeth and periodontal tissues with conventional panoramic radiographs and to clarify the usefulness of CBCT panoramic images.
Materials and methods: Panoramic images were reconstructed from CBCT images and compared with panoramic radiographs of 20 patients who underwent brain dock screening at our hospital. The images were evaluated by examining six teeth: the first molars and the right upper and lower middle incisors. The visibility of the crown, alveolar crest, root apex, pulp cavity, and periodontal ligament space were assessed, and appropriate scores were awarded. Three oral and maxillofacial radiologists independently reviewed the images, and any discrepancies were resolved by reaching a consensus. The Mann-Whitney U test was used to determine the significance of differences between the imaging modalities, with p-values of ＜0.05 were considered statistically significant.
Results and conclusion: The maxillary alveolar crest, root apex, pulp cavity, and periodontal ligament space of the middle incisor; the mandibular crown of the middle incisor; and the alveolar crest, root apex, and apical region of the right molar were significantly more visible on the CBCT panoramic images than on the panoramic radiographs （maxillary right molar pulp cavity, maxillary middle incisor pulp cavity, periodontal ligament space, and mandibular right molar apical region: P＜0.05, others: P＜0.01）. Conversely, the crown regions of all of the examined teeth except the lower middle incisor were significantly less visible on the CBCT panoramic images than on the panoramic radiographs （maxillary right molar and middle incisor: P＜0.05, others: P＜0.01）. The present study demonstrates the usefulness of reconstruction using CBCT compared with panoramic radiography.
