Radiological assessment of artificial bone defects in the floor of the maxillary sinus

Objective: To compare dental radiographs and axial high resolution (HR) CT scans for the identification of artificial bone defects between the maxillary sinus and the roots of the adjacent teeth and to evaluate the accuracy of HR-CT. Methods: Artificial bone defects of different dimensions were produced in the antral floor adjacent to 40 roots of 23 premolars and molars in 21 human autopsy specimens of the posterior maxilla. Periapical radiographs were obtained together with 1 mm axial HR-CT scans. The macroscopic and radiological findings of both sets of images were compared. Histological sections were prepared corresponding to the CT scans and the accuracy of the scans evaluated by measurement of five parameters. Results: None of the artificial bone defects could be identified on the dental radiographs. In contrast 62.5% of the antral bone defects could be identified in the axial HR-CT scans. Identification of their margins depended on the location on the tooth root, adjacent bone morphology and visualization of the periodontal ligament space. When the periodontal ligament space was visualised identification of an antral floor between 0.2 and 0.5 mm thick was feasible. Conclusion: In certain clinical situations HR-CT is appropriate for identifying antral bone defects between the maxillary sinus and the roots of the adjacent teeth.