Imaging of bone transplants in the maxillofacial area by NewTom 9000 cone-beam computed tomography: a quality assessment.

OBJECTIVES: This study evaluates the definability and usability of bone transplant imaging with the NewTom 9000 cone-beam computed tomography (CBCT) device in a retrospective evaluation. METHODS: CBCT data of 21 patients were analyzed in 2 steps. Step 1: transplants of cancellous bone (n = 6) and transplants of cortico-cancellous bone (n = 15). Step 2: The second group was further divided into nonvasculated transplants (n = 8) and microvascular transplants (n = 7). NewTom 9000 CBCT data sets were reconstructed and converted into DICOM data (spatial resolution: 0.25 mm, axial slice thickness: 0.3 mm). The OsiriX program was used to establish cross-sections in all 3 dimensions. Image quality assessment of the cross-sections was performed by 4 dentists. RESULTS: CBCT scans of cortical bone transplants showed clear borders. All cancellous transplants were poorly defined and showed little x-ray contrast. In most cases these differences seen in the descriptive evaluation were not significant in the statistical analysis of the imaging quality assessment with Fisher's exact test. CONCLUSIONS: Subjectively, the NewTom 9000 was considered by the authors to be of limited value for the evaluation of cancellous bone grafts, but to show good contrast for cortical bone grafts. The authors' subjective opinion was not supported by statistical analysis.