In vitro comparison of the imaging properties of dental materials in soft tissue using ultrasonography and cone beam computed tomography.

Accurate imaging of displaced dental materials (DMs) in soft tissues is critical for diagnosis, treatment planning, and preventing complications. The aim of this study was to compare the cone beam computed tomography (CBCT) and ultrasonography (USG) in detecting DMs embedded in soft tissues, as well as to characterize their imaging features. Fifteen DMs used in restorative, endodontic, orthodontic, and prosthetic procedures were placed in the alveolar mucosa and muscles. CBCT and USG images of DMs were obtained. Two dentomaxillofacial radiologists independently evaluated the images for detectability, radiopacity, echogenicity, and artifact presence. USG demonstrated superior diagnostic accuracy, sensitivity, and specificity compared to CBCT, particularly for low-radiopacity and superficial materials, such as paper points, wax, alginate, and acrylic. While CBCT effectively visualized high-density materials, such as amalgam, metal seramic crowns, Ni-Ti wires, and metal brackets, it failed to detect low-density objects, like paper points and wax. Intra- and interobserver agreements were excellent for both modalities. Posterior acoustic shadowing and comet-tail patterns were observed in USG. It was concluded that USG is effective for detecting superficial, low-radiopacity DMs, while CBCT excels in evaluating high-density materials, highlighting their complementary roles in managing foreign bodies in hard and soft oral tissues. These results may help clinicians select appropriate imaging modalities based on material characteristics, thereby improving diagnostic accuracy and reducing unnecessary radiation exposure. In addition, the study provides a useful reference for clinicians by outlining the ultrasonographic features of DMs.