Dental 3D printing for the technologically challenged

Let’s dumb it down to my level and start with a question: What the heck is a 3D printer? A 3D printer uses a process called additive manufacturing to build up an object layer by layer in plastic. The plastic is an ooey-gooey liquid resin that is hardened with a UV light. Most 3D printers require that you remove the slime via an alcohol bath and postcure with a separate UV light oven. For the most part, to 3D print something, you need an IOS (intraoral scanner) and a model in STL (stereolithographic file; figure 2).

Sifting through the alphabet soup

Engineers have big, smart brains. And they use said smart brains to come up with really big words and then abbreviate them to sound all cool and relatable. There are many types of 3D printers; these are the biggies: fused deposition modeling (FDM), digital light processing (DLP), and continuous digital light manufacturing (cDLM). What the heck? Stay tuned; what you need to print will help determine which abbreviation to buy.

FDM is the printer that most uncool people think about when they talk about 3D printing. You can find these in most Best Buy stores. FDM

printers use heated thermoplastic resin that is stretched into a filament and put on a spool, like a dental Rumpelstiltskin (figure 3).

You may have had experience with thermoplastics, such as making a custom tray or an NTI night guard. The filament is heated to blazing-hot temperatures and forced through a nozzle, like a hot glue gun. The resin is built up in layers, and a model is produced. FDM printers are cool because they do not need postprocessing to remove the goo, as there is none. However, the level of detail in an FDM print is pretty low.

One great use for FDM printers is the Arfona r.POD. This is the only 3D printer that is FDA-approved to print in Valplast. If you do a lot of partials or flippers, read no further. Now, if they could just make Valplast easy to polish (figure 4). If you are old enough, you may have heard of a DLP television. And if so, this is a friendly reminder to schedule your colonoscopy. A DLP TV had a small projector and a mirror, and your favorite Love Boat episodes would magically beam onto a screen encased in a wood-grain box. A DLP printer uses a very small UV light projector to beam light into a bath of flowable composite. DLP printers can print objects as small as 25 microns. There are many 3D printers in this class with varying amounts of speed and accuracy. This is the most common

form of 3D printer in dentistry (figure 5).

cDLM printers are high-speed and high-accuracy DLP printers. Many can print a dental model in less than 10 minutes. But like Spiderman, with great power comes great price tags. Or something like that. cDLM printers are usually paired with an oxygen or nitrogen tank to help speed up the printing process (figure 6).

In addition to being somewhat challenged in the thinking arena, I am also thrifty (translated dumb and cheap). Most 3D dental printers range in price from $4,200 to about $25,000. There is another class of printers known as LCD (liquid crystal display), which range in price

from $200 to about $1,000. So, of course, I was intrigued. However, I have found that these types of printers can be problematic.

Instead of a projector, an LCD printer uses a good ol’ phone screen. These screens are low in cost, but, anecdotally, I have found big variations in reliability, accuracy, and ease of use for these printers. So, in a nutshell, pay up and get a decent printer (figure 7).

OK, now you know enough to be dangerous. The next question is, “What can I print?” You can print anything in dentistry that was formerly made with stone, plastic, or wax. In my practice, I print orthodontic models for aligners, dies, implant analog models, implant surgical guides, diagnostic wax-ups, dentures, and both tooth- and implant-borne temporaries. We are constantly reminded that four years in dentistry and possibly four more in an orthodontic program can be replaced by a YouTube video and a catchy billboard. A number of my patients have used DIY aligner services with varying degrees of success. Why would they even do that? Well, ortho is expensive, and to go one step further, aligner lab bills are expensive too. 3D printing allows me to make my own aligners in-office and reduce my fees to stay

competitive with the tooth movers at the kiosk in the mall (figures 8 and 9).I have always been a big fan of implants—the dental kind. But just like ortho, the lab bills associated with implantology can be a bit pricey. I was paying about $2,000 a month on surgical guides, as well as thousands on implant analog models, implant hybrid models, and temporaries. Surgical guides can be had for less than $30, analog models for less than $50, and hybrid temporaries for a few hundred. What’s really cool is that a lot of the inaccuracy in hybrids and analog models is eliminated because we don’t have to stick parts into a PVS impression and hope they stick in the stone (figure

10).

I hate dentures. There, I said it. I do all the steps. Heat up compound to lip-melting temperatures, and then pull and palpate my patient’s face until they want to call the cops. Then, after the 20 post-op adjustments, it’s still hard to make a buck. A set of digital dentures can be 3D printed for less than $50. Although I confess that I don’t do many, digital dentures have been great for lots of my friends who treat Medicare patients because the reimbursement is low and the cost of making dentures allows these patients to get their teeth (figure 11).

I think one of the coolest uses for 3D printing is DSD (digital smile design), or just name one of the 50 permutations of this concept. Before

3D printing, I paid about $50 per tooth for a lab technician to masterfully heat up a candle and shape it into a tooth. With the efficiency and symmetry of digital, lab technicians are using a mouse instead of a wax spatula and still charging $50 per tooth. There is lots of free software out there (Blue Sky Plan or Meshmixer) that allows dentists to design their own digital mock-ups. Or you can pay a designer between $2 and $10 per tooth to design it for you.

You can then print the digital wax-up and use it for a prep guide, take a putty wash index and make temporaries in the mouth, or print the shell temporaries yourself. You can also print a gingivectomy or crown-lengthening guide based on the shape of the ideal tooth setup (figure 12).As digital dentists, we have been encouraged to be model free for years. With the dawn of 3D printing, we can get that model we see on the screen into our hands. 3D printing allows us to make dentures, surgical guides, aligners, die and model work, temporaries, and more!

We have finally arrived in the era of dummy-proof 3D printing.

Read also:
3D printing: The technology of now

AUGUST de OLIVEIRA, DDS, graduated from the University of Washington School of Dentistry in 1997 and completed his general practice residency in Los Angeles in 1998. He has been lecturing on 3D technology since 2004 and has written three dental books: Implants Made Easy, Guided Implantology Made Easy, and Dental 3D Printing Made Easy. Dr. de Oliveira lectures for Implant Direct and Dentsply Sirona. He lives and practices in Los Angeles, California.