3D Printing: Bigger & Better

Dental Products Report, Dental Products Report September 2024, Volume 59, Issue 8

3D printing technology is the next big thing, and we are going to experience another digital workflow that will change dentistry for the better sooner than you think.

To kick things off, I have some questions for those of you who have been in practice 10 to 15 years or longer. Do you miss the darkroom? Do you miss having to dispose of all the chemicals properly and paying for a hazardous materials disposal company to remove them from the office? Do you miss waiting 5 minutes for a film to spit out of the processor while running 30 minutes behind on a complex endodontic case? How about films getting stuck in that processor and disappearing until the next time someone cleaned the unit? Yup, I don’t miss that either. I started using digital radiography in the early 2000s, and when I built my new office in 2007, the architectural plans didn’t even include a darkroom. I don’t pine for those days, and I’m sure you don’t either.

The other thing I did when designing the new office was to make the lab area considerably smaller. I gladly admit that I gambled a bit by doing that. However, I did it with a little perspective on the future. I had been using in-office CAD/CAM for a few years but had stepped away by 2005. At that time, I wasn’t getting the fit and feel I got from lab-fabricated restorations. Yet even though I was back to taking analog impressions, I was pretty sure I knew where the industry was headed. Fortunately, my gamble paid off. One year after moving into the new office, I brought in the original Cadent iTero system, and we were going to digital impressions rather quickly.

The Brink of Progress

I bring up all these old stories because I want you to know we are on the brink of another wholesale change in the dental industry. 3D printing is about to do the same to dentistry as digital radiography did. In the not too distant future, we will experience another digital workflow that will change dentistry for the better––much better. For most of 2024, I have been immersed in the world of 3D printing, and I think it’s time you learned more about it.

Some of you are saying, “Flucke, 3D printing has been around for 5 or more years and hasn’t caught on. What’s the big deal now?” My answer is that a lot has changed since we first saw 3D printing in dentistry. The best example I can give is to look at artificial intelligence (AI).

I don’t think many will argue with me that 2023 was the Year of AI in Dentistry. AI seemed to come out of nowhere. Several companies had released dental products in 2022, but in February of 2023, ChatGPT was suddenly a huge news story. The press coverage of AI was immense, and suddenly AI was of interest to everyone. However, the tech had been in development for years. While it seemed to emerge out of nowhere, in reality it had been building slowly under the radar for over a decade.

We are seeing a very similar situation with 3D printing. It has been around in dentistry for 5 to 10 years but has had limited scope. But trust me when I say that the next 12 to 18 months will see a major shift in our workflows as this tech goes more mainstream.

Workflow

The proliferation of intraoral scanners is one big reason. At least 30% of offices now have a scanner, and surveys indicate that for those who don’t, purchasing one is high on their list of must-haves. We have 2 scanners in our office, both used multiple times a day. Not only the doctors but also the hygiene team use them.

Many offices now include a full mouth scan in their new patient intake process. That means a large percentage of offices are moving in that direction. Yet even with scanners becoming increasingly intrinsic to what we do, many offices still take physical impressions for various services other than fixed prosthetics. If a patient comes into the office and has a full mouth scan but also wants to undergo at-home whitening, many offices pull out alginate, pour the impressions, and then create the trays with a vacuum-forming device. In the sense of a totally digital workflow, that is like confirming an appointment by fax. Once the scanner digitally captures the patient data, having a digital solution just makes sense.

The Process

However, that digital solution must be simple, which brings us to the other part of why 3D printing is poised to change dentistry significantly. Until recently, designing anything produced by a 3D printer was cumbersome and complicated to learn. The companies that make these amazing pieces of hardware quickly realized that a busy office has trouble integrating any technology with a significant and challenging learning curve. No one wants to have to open Adobe Photoshop and spend 30 minutes editing just to post a photo on Instagram. The 3D printing companies quickly came to the same conclusion and set about creating design software to allow quick, easy, and reliable processes to generate the majority of projects a dental office might require.

These software solutions are available now and have essentially solved that problem. Many are cloud based, which simplifies things even more. Cloud-based systems update independently with no user intervention required and back up projects every step of the way. All the office needs to do is upload the STL files from the scanner and select the project required. The system then walks the user through the process.

Let’s use a bleaching tray as an example. The upper and lower arches are uploaded, the “bleaching tray” option is selected, and the user creates the reservoir area by drawing the proper shape on each tooth. The system then proposes a margin for the tray that the user can edit by simply clicking on it and dragging it to the desired area. When the design is completed, the finished project appears on the screen so the user can be sure it is exactly what they want. Many of these design programs integrate AI into the design, so the design process is often a matter of just clicking “next” and moving to the next step. I am really excited about this, and you can expect these systems only to get smarter as they continue to get feedback from users and the software engineers improve these already intelligent platforms.

The finished project is then downloaded and loaded into the printer’s “slicing/nesting” software. This software shows the user the appliance’s position on the printer bed. Once confirmed, the software converts the STL file into a language the printer understands, and the project is printed.

The design project I just described takes only a few minutes. The advantages are quite clear when you think about the analog process (and mess) of making an impression, pouring, trimming the model, blocking out for the whitening agent, heating and vacuuming, and trimming the tray. Of course, one of the other great advantages of having a digital design is that if the patient loses their trays or their pet destroys them, making a new one is as easy as pushing a button. (By the way, are you as amazed as I am at how often pets chew up dental devices?)

The project is printed using a liquid resin––and hundreds of resins are on the market. Thus, no matter what type of project you need, chances are there is a resin that will meet your needs. You can create bleaching trays, soft and hard occlusal guards, orthodontic retainers, surgical guides, models, dentures, and more.

The other thing the slicing/nesting software does is add supports to the project. These are necessary to help build the project. The resins are liquid and, like composites, are light cured. The printer builds the projects in layers, again similar to composites. Because the printer cures the projects in layers, supports are needed to ensure printer accuracy. The supports are tiny cured bars that stabilize the resin. When the project is completed, it is removed from the printer with the supports attached to it.

The project is then placed in a wash station that circulates isopropyl alcohol, removing any remaining liquid resin. Once the wash is completed, the project is put into a curing station, essentially a box with high-intensity LEDs on all sides. The project then goes through a set “postcure” time to ensure a total and complete cure. Once the postcure stage is complete, the supports are removed, and the project is polished.

Limitations?

3D printers are incredibly precise, with many having an accuracy of 50 µm. That means pairing an intraoral scanner with a 3D printer gives results that meet our profession’s extremely high demands. When I first began using the iTero back in 2008, I immediately noticed how much faster our crown seat appointments were. The tech was precise even nearly 2 decades ago, but I hadn’t expected that much precision. Of course, the current generation of scanners has only got better. (Since 2008, Align Technology’s iTero systems have made even greater strides, and other manufacturers have developed high-quality scanners that give clinicians numerous choices to find the solution that best fits their practice.) The combination of scanner and 3D printer offers serious advantages over analog systems. Your in-office lab will soon be used for fewer and fewer things.

Many of you will have noticed that I haven’t mentioned permanent crowns in my discussion and may be wondering why. I want to state my feelings on the subject for the record. My opinion is based on a couple of factors. The first is that I have an in-office mill. In April 2022 we installed a DGSHAPE DWX-42W mill, producing fantastic results. The main materials we use are presintered zirconia and prefired lithium disilicate. These materials eliminate the need for an oven and are ready to cement after being polished. Both materials have a long track record of clinical success, and I am incredibly confident in their long-term viability.

The second factor is that resins for 3D-printed crowns don’t have that same track record, which is why I am still not printing permanent crowns personally at this point. I realize some people are, and I have no problem with that. As I already have an in-office solution that works well for me, I am still watching and evaluating this permanent crown aspect. I have no doubt that someday soon, this will become a viable option for all of us. I have been practicing for a while, and over those years I have occasionally pushed the envelope with materials. Some of those decisions have been ones I regret. I have redone cases because a new material has fractured or not held up, and I admit those experiences have affected how I view crown materials. We all have our biases, and I want to be sure you understand mine. If you are currently printing crowns and having success, I would love to hear more about your experiences.

Advanced Applications

Other than anything permanent, I am all in on 3D printing. I am a big fan of how the manufacturers approach this. There are so many everyday applications for this tech, and I appreciate that those companies have noticed this. There is no need for a patient to wait 2 weeks or more for a slam dunk occlusal guard or anything else that can be easily created in a day in the office. I can envision a patient being diagnosed as a candidate for implants and having the guided surgery performed the very next day. The process is now that simple.

I am also excited about 3D printing to help with full arch or full mouth reconstruction. One of the most difficult things we do is correctly open a collapsed bite. With the right design software, those cases can be created digitally, and the temporaries fabricated on a 3D printer. If you place the

temporaries and the next week determine that the vertical needs to be changed, you simply correct it in the software and print new temporaries to the corrected vertical. If a fractured temporary occurs, reprinting a new one is a simple process. The same can be said of dentures. If a patient drops one and it fractures, printing a new one is straightforward. I’ve even heard of doctors providing 2 dentures at delivery so the patient always has an identical backup if disaster strikes.

Wrapping Up

Get ready. 3D printing is going to change our profession, and I believe the change will happen quickly. After my deep dive into 3D design and printing this year, I am confident we will see some profound changes in the near future. If you have invested in companies that make plaster and stone, now might be a good time to put that money to work for you elsewhere. If you are thinking of building a new office or new office space, I would think about where you can better use the space you might have been considering for your large in-office lab. Square footage is expensive, and you might not need as much room for that lab as you thought.

I sometimes think about the days when I would watch a talented dental assistant squeeze equal lengths of an impression material out of 2 tubes and mix it to a perfect consistency with a spatula before loading my syringe and then loading the tray. I don’t sigh longingly and think, “Ah, the good old days.” Instead I think, “I can’t believe we ever did it that way!” Soon we will feel the same way about mixing stone, pouring impressions, and trimming models. Imagine the possibilities.