The availability of this technology will undoubtedly expand the use and application of 3D imaging in the field of orthodontics. Maxillofacial cone beam imaging provides clinicians with an opportunity to generate 3D volumetric renderings using relatively inexpensive third party personal computer based software. This was performed by a sequence of preset volumetric orientations.
Dolphin imaging chatworth software#
The Dolphin 3D software enabled measurements to be performed from different views using rotation and translation of the rendered image. Then, the cephalometric landmarks were located and marked on the image. Next, the 3D image was reoriented such that the Frankfort horizontal plane was parallel to the lower border of the screen display in both sagittal and coronal projections. This provided 3D renderings which demonstrated visual differences, depending on the number of projection images used in the reconstruction ( Figure 4). This involves generating an image of the skull by manually adjusting the threshold of visible pixel levels, a process called segmentation ( Figure 3). This software is capable of generating 3D shaded surface display volumetric rendered images using the entire volumetric data set. All reconstructions and measurements were performed on a 20.1-inch flat panel color monitor (FlexScan L888, Eizo Nanao Technologies Inc, Cypress, Calif) screen with a resolution of 1600 × 1200 at 85 Hz and a 0.255 mm dot pitch, operated at 24 bit. The CBCT data were imported in DICOM multifile format into Dolphin 3D (V.10, Dolphin Imaging, Chatsworth, Calif) on the same computer. The mean of the measurements served as anatomic truth. To establish the true distances between the selected anatomic points, measurements were made by the principal investigator and a research associate three times independently using an electronic digital caliper (27-500-90, GAC, Bohemia, NY). 13, 14 The dimensions between specific points provided 16 linear distances commonly used in cephalometric orthodontic analysis ( Figure 2). Operational definitions were developed as elaborations or modifications of those presented by previous authors. Landmarks were chosen to provide representative linear dimensions in vertical, transverse, and horizontal planes. Fifteen craniometric landmarks, of which nine were bilateral ( Table 1), were identified on each skull using an indelible marker providing 24 anatomic sites.
Dolphin imaging chatworth full#
The sample consisted of 19 dry dentate human skulls with a stable and reproducible occlusion, presence of a full permanent dentition, and similar skull size. This observational cross-sectional in vitro experiment was approved by the Institutional Human Remains Committee at our university. Because the fiducial landmarks on the skulls were not radio-opaque, the inaccuracies found in measurement could be due to the methods applied rather than to innate inaccuracies in the CBCT scan reconstructions or 3D software employed. Reducing the number of projections for 3D reconstruction did not lead to reduced dimensional accuracy and potentially provides reduced patient radiation exposure. No differences were detected between CBCT scan sequences.Ĭonclusions: CBCT measurements were consistent between scan sequences and for direct measurements between marked reference points. CBCT resulted in lower measurements for nine dimensions (mean difference range: 3.1 mm ± 0.12 mm to 0.56 mm ± 0.07 mm) and a greater measurement for one dimension (mean difference 3.3 mm ± 0.12 mm). The average skull absolute error between marked reference points was less than the distances between unmarked reference sites. Results: No difference in mean absolute error between the scan settings was found for almost all measurements. The mean absolute error and modality mean (± SD) of linear measurements between landmarks on volumetric renderings were compared to the anatomic truth using repeated measures general linear model ( P ≤. The skulls were imaged with CBCT (i-CAT, Imaging Sciences International, Hatfield, Pa) at three settings: (a) 153 projections, (b) 306 projections, and (c) 612 projections. Materials and Methods: Sixteen linear dimensions between 24 anatomic sites marked on 19 human skulls were directly measured. Objective: To compare the in vitro reliability and accuracy of linear measurements between cephalometric landmarks on cone beam computed tomography (CBCT) 3D volumetric images with varying basis projection images to direct measurements on human skulls.