Ever have a case that requires both implants and orthodontic care? Of course, you have, or will in the future. Would it ever be beneficial to have the implants in place before the ortho is started? The answer is “yes” for two reasons.
First, and perhaps most important, is that the implant could be used as anchorage for the orthodontics to assist in movement.
Think about it. Orthodontics traditionally pits teeth against each other to create forces to move things into the right positions. For some time, mini implants – also known as temporary anchorage devices (TADs) – have been used to assist with movements that are difficult or just not possible with teeth alone, so if we can have a restorative implant placed and integrated it can act as a sort of super-TAD.
The second reason is that placing the implant early (during or before the orthodontics has started, rather than after the orthodontics is completed) means you do not have to wait for its integration to restore it.
So, how do you predictably place an implant before orthodontics so it is in the right position for where the teeth will be post-ortho? The good news is that with a little planning, it can be done when needed or desired. The better news is that with today’s digital technology, we can do it easily – or, dare I say, easier than we could with past analog methods.
In this article, I will break down the steps needed to pull this off. While I will primarily focus on doing this digitally, I will also describe how you could achieve a similar result in the analog world. However, in my opinion, there is more potential for error when it comes to analog methods.
1. Obtain a pre-op model
In the digital world, the most efficient way to do this would be with an intraoral scanner and direct scanning of the patient's arches. It is important to note, you need to scan both arches fully, including the bite. In the analog world, you could simply take traditional impressions and pour models. As an in-between option, you could scan stone models to generate digital models.
2. Preform the orthodontics virtually
The next step is to perform the orthodontics on the models you have created. To do this you first need to duplicate your models, which is super easy, more efficient and accurate with digital models. The key part is one set of models must remain totally unchanged and you must maintain reference points between the two sets, which will allow you to merge or superimpose the two sets onto each other accurately in the digital world. In the analog world, you would need points identical on both set of models that you could measure from.
3. Identify were the implant needs to be after the orthodontics
Obviously, this step is straightforward and is done on the post-orthodontic model.
4. Identify were the implant needs to be pre-ortho
This is where having two sets of models, one pre-ortho and one post-ortho, with at least three identical reference points on each is critical. Keep in mind more reference points are a good thing, but three is the absolute minimum and the more spread out these points are the better. These reference points are important because they allow you to index the desired implant position to your pre-ortho model.
For the example I am sharing here, I did this by positioning the post-ortho model with the implant position marked over or onto the pre-ortho model. In this case, my reference points were all the teeth on the right side of the models, since my orthodontist had only moved the teeth on the left side in the post-ortho model I was using.
Figure 1 provides an example of the digitally merged models with my marker ring, signifying where I want to put the implant. In the image, both my pre-ortho model and marker ring are transparent.
Figure 2 shows the same image with both models and the marker ring opaque.
Once this is done you can digitally “drop out” the post-ortho model, leaving only the implant position marker and your pre-ortho model like you see in Figure 3.
In the analog world you would use three or more reference points on the post-ortho model by measuring in a straight line from each of these points to the desired implant position on the post-ortho model. You would then measure from those same distances from those same points on the pre-ortho model thus triangulating the position of the implant onto the pre-ortho model.
5. Fabricate your surgical guide
The next and final step is to design and fabricate your surgical guide. If you have followed the steps above, you now have a pre-ortho model with your desired post-ortho implant position designated. With this information, the guide fabrication is simple. If you are playing in the digital world and have already been making surgical guides, then you also have the information you need to proceed normally. If you are new to digital guides, then you have options. One option is to outsource the guide design and fabrication. The other option is to perform the design and fabrication yourself.
For the case I am using as an example, I chose to design the guide myself and then print it. In this case, I used free software from Blue Sky Bio. The only cost with this software is the .STL file export so you or your lab can print your guide. It is worth noting that the cost of file export is reasonable. Blue Sky often runs specials or introductory offers that give you a few free exports. The other option if you want to stay in the digital world is to buy software. There are many, at varying costs, and a quick web search will yield a myriad of options.
If you are playing in the analog world, then just proceed as you have in the past. As you know, the options here are numerous.
There you have it! Now you have a method to have implants placed pre-ortho for post-ortho success.
In the digital world, there are a lot of ways you could handle the files and images to get to the same result. If you are heading down that path and trying this for the first time, don’t be tied to doing it exactly as I did here. The key is to just apply the principles.
John R. Carson, D.D.S., is a member of Spear Visiting Faculty and a contributor to Spear Digest.