ObjectivesThis study sought to assess the diagnostic value of ultrasonography (USG) and cone-beam computed tomography (CBCT) for the visibility of periodontal defects.Materials and methodsWe created 37 periodontal defects (dehiscence and fenestration) in fresh sheep mandibles. Two dentomaxillofacial radiologists assessed the CBCT and ultrasonographic images for the presence of defects. Kappa statistics was used for evaluating the inter- and intra-observer agreement. Sensitivity, specificity, diagnostic accuracy, positive predictive value (PPV), and negative predictive value (NPV) for each radiographic technique were calculated.ResultsInterobserver evaluations revealed moderate and good agreement for USG and very good agreement for CBCT in visibility of dehiscences and fenestrations. It has been determined that USG and CBCT have similar sensitivity and specificity values.ConclusionsUSG can be used as an alternative diagnostic method to CBCT in the evaluation of periodontal defects.Clinical relevanceThis study has shown that USG can be an alternative diagnostic method to CBCT in imaging dehiscence and fenestration in the alveolar bone, which is the hard tissue component of the jaws. In addition to clinical probing, USG, which is a radiation-free imaging method, can be used to provide additional information in the visibility of defects. Such studies will increase the experience and knowledge of physicians and will allow USG to take a greater place in dental practice.