The dream is to create the most predictable and gentle treatments with clear aligners and fixed appliances. Imagine being able to do a data merge between an IO scan and a CBCT scan of the patient. The SureSmile planning software simulates the movement of the roots in the bone throughout the orthodontic treatment.
Especially treatments with clear aligners seem to be an obvious choice to use a technology like the one mentioned. Since most clear aligner treatments are performed by general dentists, without any significant background in orthodontics.
Not only would it be beneficial to ensure that all tooth movements occur within the cortical bone. It would also create better opportunities to plan more complex treatments, where ideal conditions for the insertion of implants after tooth straightening must be created.
In principle, the technology could take backwards planning to a whole new level.
Can CBCT be an advantage?
If we can simulate and visualise how the roots move during the orthodontic treatment we have planned, it will be possible to avoid moving teeth out through the bone.
The mandibular front is particularly considered to be at high risk when we move teeth. Most dentists who work with clear aligners have gradually become aware that the clear aligner manufacturers' preference for quick shortcuts can be harmful to patients. One example is round tripping, which most often leads to a significant risk of severe gingival retractions, as a result of the incisors being moved out through the bone during a clear aligner treatment.
In implantology, there are some specific requirements for the insertion of implants. The amount of bone and the distance to neighbouring teeth, are crucial. The combination of guided or navigated surgery and optimally simulated tooth movements prior to the insertion of a fixture, could raise the quality of the more complex treatments to a whole new level.
Restorative treatment is best when the roots are in an optimal position. Partly in terms of the load on the teeth, partly in terms of aesthetics. It is much easier to create a beautiful smile if you do not have to visually compensate for the inadequate angulation of the teeth. Working with the principles of digital smile design, or similar, will provide much more ideal conditions for performing an optimal post-orthodontic restorative treatment, if you have maximum control over the precise position of the teeth. Not only over the gingiva, but also in the bone.
If we are able to follow the movements of the teeth on a 3D simulation of the patient's real conditions, we will, in principle, be able to prevent many kinds of damage to patients. In other words, we will be able to achieve much better risk management.
Moreover, the technology will potentially improve our ability to control the predictability of the movements we plan.
Does it work?
We have tried to work with Dentslpy Sirona's new technology and are not impressed. The radiological conditions on the cases we have tried the technology on have been relatively simple and should therefore be ideal cases to try it on.
Initially, the way it's all built looks reasonable. The software does an autosegmentation of the teeth in the CBCT scan and marks the teeth in a distinct contrasting colour on the 3D model of the jaws. In this way it becomes clear where the roots are located. Or rather, it becomes obvious if the roots move out through the simulated bone surface.
Surface simulation only
It is only a 3D surface model of the jaws that can be used to look at a simulation of the movement of the teeth. If you have worked with CBCT scans as part of your daily routine. You will know that the surface scan is a wonderful visualisation tool if you want to show your patient something on the screen.
Unfortunately, it is not a useful tool when you need to see or measure something accurately. Here you need to look at the radiological 2D slices (Typically visualized in 3 different planes at once).
The new software upgrade at SureSmile does not allow you to see any simulation directly in the X-ray visualization. It would be nice, for example, to have a blue line marking the initial position of the tooth and a red outline marking the simulation of tooth movement.
We speculate that the poor visualisation is related to the software's challenges with autosegmentation. Avoiding the user's ability to control the quality and precision of the segmentation also avoids the risk of criticizing the software on this point.
For the human brain, it is relatively easy to tell the difference between tooth and bone on an X-ray. At least if you are trained in reading X-rays. When it comes to CBCT scans, it can be a bit more challenging to tell the difference, as the resolution typically appears more coarse-grained than on a full-sized x-ray.
For a computer, it is extremely difficult to define the boundary between tooth and bone. When it comes to visualising tooth movement in bone, it is extremely important that the X-ray software is able to automatically split the elements of the scan.
If you have tried to manually define what is tooth and what is bone, you will know that it is an extremely time-consuming task to segment just one tooth from the bone. If you have to do it for all the teeth, it is by no means cost-effective to do in your dental practice. That's why it's important that the software can do it for us.
The SureSmile software does a decent job when it comes to autosegmentation. Decent because we know how difficult it is for the software to do the job. We have seen relatively large glitches in the autosegmentation and therefore miss the ability to perform smaller fixes. Just as we miss the ability to see what is happening directly in the X-ray visualisation in all 3 planes and not just on an imprecise 3D surface simulation.
3D simulation of tooth movement in orthodontic treatments is likely to become a standard procedure in the future. Unfortunately, the SureSmile software has not been developed to a stage where we believe that any useful knowledge can be gained for treatment planning.
At best, it is a waste of time.
At worst, patients are given an increased amount of X-rays without adding any value.
Therefore, at present, we cannot recommend the SureSmile integration of CBCT as an element in the simulation of tooth movement in orthodontic treatment.
Want to know more?
Or do you need help getting faster and more predictable treatment results with SureSmile?
Then feel free to contact AlignerService.
Many kind regards
Jesper Hatt DDS
T: +41 78 268 00 78