3D less than 2D Pan + Ceph
Martin Palomo give a presentation showing how CBCT scanners have dropped radiation dosage.
The technology used to drop 3D dosage apparently might not be applicable to 2D scans, so in
Toni Magni asked if it's possible to use the same technology used to reduce 3D radiation to reduce 2D radiation. 3D is based on redundant information, while 2D is a one shot deal, so it's harder to improve technology on a system that doesn't have room for improvement. So, the group agreed that it's not possible to reduce 2D further.
Franco Magni suggests that the CBCT PAN at low dosage is not clinically acceptable, as it's resolution is too low.
Manish shows some real patient data of a QuickScan+ at 4.8s (very low dosage and resolution). Pano does not do justice in assessment to pathology for sure. He's not looking at pano's anymore for pathologies. He uses 3D reconstruction only.
Resolution: Game Over
The group convened that in 2014 CBCT now replaces Pan screening image for orthodontics.
Cephalogram has staging power for:
- Norms
- Serial evaluation
Coffee Break
3D Norms
Can't make 3D models from CBCT because of resolution: not possible to have good resolution enough to build appliances and keep the low dosage. So surface scans are necessary. Right now the surface scanners are therefore developing in parallel with CBCT.
Can we extract stuff from 3dMD and compare/overlap on CBCT. Carla Evans says it's hard to overlap on CBCT cuz there is distortion on the 3dMD. It's easy to keep the subject steady, as they are just insant flashes. They can be setup to make a 360 surface of the head, but the problem is the hair, which gets captured as surface.
At Bolton Brush, there are 3D landmark data from the study thanks to the PA+Ceph combination taken w/o moving the patient.
What raw material is available?
- cross-section CBCT age 7-40
- Longitudinal face scans
- 3D Bolton landmarks
- 2D midlines
Lunch Break
The problematic of certain article reviewers rejecting articles solely based on the technique used was discussed. For example, a reviewer that is against CBCT could reject all studies that are CBCT based.
Intra-oral scanning
Air force wants to identify people without getting close to them. They are interested in what clinicians are using, how accurate they are to be able to identify people quickly in extreme situations. UIC is testing a scanner by Ormco to see how it can be used for this project. Each scan takes about 7 minutes for both upper and lower arch, but when they tried, the first time it took them 1 hour but with practice 14-15 minutes for the entire mouth. Resolution is relatively high, chipping can be detected. This scanner does not require powdering. Can use scanner in wet environment, since it requires little time. It requires multiple scans off of multiple surfaces, so it can reconstruct thenetire surface in post-processing. UIC did some comparisons with iTero for rugae studies, but it's convenience is mostly based on color and size (portability).