Printing an Occlusal GuardBy John Carson on August 15, 2019 | 2 comments
If you’re a restorative dentist, chances are you make occlusal appliances. There is also a good chance you make or would like to make at least some of these appliances in your own office.
If you are already making your own, you have learned while the process is labor-intensive, it becomes simple once you have the right equipment and have done a few. The good news is with the advent of 3D printing we can now remove a good portion of the labor.
Keep reading for a rundown of how printing an occlusal appliance in your own office can flow.
Step 1: Capture your records
This is simple: you need the same records for printing as you do for our traditional old-school fabrication methods. How you get these records is up to you! You can keep it old-school and take traditional impressions and bite records, then scan your poured mounted models, or go high-tech and capture everything digitally.
Obviously, there are pros and cons to both options. Perhaps the biggest upside to keeping it old-school and taking impressions is that you’re probably used to the process and it’s likely something you can delegate to your assistants. Clearly the biggest downside to sticking with traditional records is that you will need to digitize them by scanning, so you are adding a step.
On the other hand, with a full high-tech approach, the pros include having no traditional impressions (which patients often find super cool) and providing everything digitally from the get-go. The downside is you must learn to scan in the mouth and gather those digital records, and there can be a bit of a learning curve.
Step 2: Design the appliance
This step can by far be the most technically challenging step, especially if you are going to do it on your own, since that means you must buy and learn new software, which can be pricey and tricky to learn.
Yes, there are programs that are or are nearly free to use, like Meshmixer. However, they are not specifically designed for dental applications and can take considerable time to learn. On the opposite end of the spectrum, you have programs like Exocad that will set you back thousands of dollars. The good news is there is a market for new dental-specific programs, and they are being developed.
If I’ve got you discouraged, stay strong. I have good news. If you don’t want to design your own appliances, there are plenty of labs out there that will be happy to do this for you for a nominal fee!
While I was initially set on getting and learning software to do this myself, outsourcing has just made things easier for me and my team for now. It’s super economical and efficient.
Here are some samples of what I get back. The first image shows a lower splint.
While this is an example of an anterior deprogrammer:
Step 3: Load your file or files for printing
The main thing you must do here is orientate your print correctly for your given case. With appliances like this, the print will require some supports for it to print correctly.
It is important to position the print so that the supports are not on the intaglio, as this would affect the fit of your appliance. The other thing you must consider is that printing times are affected by the total number or width of the things you’re printing, while others are affected only by the height of things you’re printing.
Step 4: Print your appliance
Printing the appliance merely takes a simple click of a button once you have your file and the appropriate resin loaded.
Straight out of the printer you will have something like this:
For reference, NextDent Ortho Clear resin was used here, and you can see we printed two appliances at the same time.
Step 5: Post-processing
After printing, your print will be hardened to an initial degree and will need additional processing to fully cure and finish it.
The first step is to wash the print in 91% (or higher) isopropyl alcohol and post-cure it. For more details on post-processing, check out Spear Digest's “A Primer on 3D Printing.” In the article, I discuss post-processing in more detail.
In that article, I show processing that does not include supports, though the process is the same.
Step 6: Remove the supports
This is as simple as cutting off the supports with clippers like these:
Follow by smoothing the remaining nubs with an acrylic bur.
Step 7 (optional): Fit the appliance to a physical model
This step is optional, but I recommend it since it can save you lots of chair time. One thing to be careful of is using stone models that are easily abraded as you try to tightly fit a device on and off.
For this reason, I recommend using printed models if you are going to do this step, as I have found them more abrasion resistant.
Step 8 (optional): Adjust the occlusion
Another optional step, especially for something like an anterior deprogrammer, is to check and – if needed – dial the occlusion in on a set of mounted models prior to delivering it to your patient.
The advantage to doing this is just like checking your fit in Step 7. It can save you chair time and make your delivery appointment go smoother and faster.
Step 9: Finish and polish
This is super simple. Personally, I like to use these polishers from Brasseler:
Printed resin polished with these polishers ends up looking like this:
It turns out nice and smooth with a matte look. If you desire a high shine, the best way I have found to coat the exterior is with Palaseal, which will leave you with a glossier look like this:
Step 10: Delivery
This is just like delivering any appliance fabricated with traditional methods, especially if you did Steps 7 and 8.
John R. Carson, D.D.S., is a member of Spear Visiting Faculty and contributor to Spear Digest.
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