Our research is focused on integration of CBCT and antiscatter images, which is inevitable in creating a virtual hat. So far, those three images are markedly using the best film method, which is surface-based. This research is to introduce a new integration method based on AI-assisted digitization and to evaluate its accuracy.
Artificial intelligence has been used to predict treatment outcomes and digitize landmarks in supplementary radiographs or CBCT images. There are some commercial softwares available. This program adopts AI-assisted machine learned automation in digitizing landmarks in CBCT and also calibrating manually picked landmarks in dental images.
The interop job of the lab team showed a significant and almost perfect ICC in each method. The main difference showed no significant between the first and second registrations in each ABR and SBR in between both methods. However, their ranges were lower with ABR than with the SBR method.
The ABR protocol not only improved the accuracy, but also significantly reduced the merging time. While the SBR method took three to four minutes, the ABR program only required about 50 seconds for landmark selection, 40 seconds for DDI landmarks and two to three seconds for CBCT and DDI merging. To begin, launch the ON3D software on the computer, click on the Load DICOM File icon to import the files, select any DICOM file and click Open.
Click on the Reorientation icon in the Landmark panel. Then click the V notch of the frontal bone in the 3D view. Scroll up and down the Sagittal view to find the anterior-most point, then click the point where the frontal nasal suture meets the nasal and frontal bones.
Similarly, scroll through the Coronal view and click to determine the horizontal position of the nasion. Next, click on the most inferior point on the margin of the right orbital contour. Then scroll through the Coronal view to find the lowest point on the inferior margin of the right orbit and click.
Now in the Sagittal view, click on the most superior point of the right maxilla that constitutes the lower boundary of the orbit. Scroll through the Axial view, then click to align the red cross against the point where the eye orbit rims meet. Click the most inferior point on the margin of the left orbital contour, then press the most superior point of the outline of the right external auditory meatus.
Click the lowest point of the right temporal bone in the Coronal view to determine the horizontal and vertical positions, adjust the vertical and anterior posterior positions by clicking on the most superior point of the outline of the right external auditory meatus in the Sagittal view. Next, scroll through the Axial view to where the external auditory canal appears and the line of the temporal bones disappears, then click. Choose the most superior point of the outline of the left external auditory meatus.
Now click on the Done icon to finish the reorientation of the reconstructed craniofacial model. Then press the Preliminary Landmark Picking icon in the Landmark panel. Press the Execute icon in the Preliminary Landmark Picking panel to automatically choose preliminary landmarks.
To modify the landmarks, press the Manual Landmark Picking icon in the Volume tab, then make the necessary adjustments and press Done to confirm the placements of the landmarks. Press the Registration of Dentition Scan icon in the Tools panel. Then select the maxilla dentition and click on the Load icon in the Dentition Registration panel.
Now choose the STL files of the same patient with the CBCT model in the folder to load the maxilla dentition STL files. Switch the blue triangular arrows back and forth to pick the mesial buccal cusps of the right left maxillary first molars, and the right maxillary central incisor midpoint as registration landmarks. Finally, press the Done icon in the Dentition Registration panel and click on the Yes icon to confirm the automatic registration.
To merge the mandibular dentition, choose the mandible dentition and click on the Load button in the Dentition Registration panel. After generating the STL files, choose the mesial buccal cusp of the right left lower first molar and the right lower first incisor midpoint as registration landmarks. Now click on the Pick Registration Landmark icon in the Dentition Registration panel and press Confirm to modify the merged model.
To obtain the 3D coordinates of the landmarks, click on the Manual Landmark Picking icon in the Volume tab, or click on the Analysis tab to obtain the 3D coordinates of the landmarks. Lastly, click the Analysis tab and press on the Data Export panel followed by the Landmark icon to export the data as a file.
