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Robert Elsenpeter is a freelance writer and frequent contributor to Dental Products Report and Digital Esthetics. He is also the author of 18 technology books, including the award-winning Green IT: Reduce Your Information System's Environmental Impact While Adding to the Bottom Line. As such, he’s particularly interested in the technological side of dentistry.
Technological and materials advances mean big things for labs, doctors and – ultimately – patients
The mass emerges slowly and steadily, still wet from the primordial ooze from which it originated. As it rises, its features are gradually revealed. With every passing moment, it becomes more definite, more apparent that something it is metamorphosing from, seemingly, nothing.
No, this isn't a scene from the 1991 movie “Terminator 2” – it is the model of a lower arch being 3D printed on an M2 3D printer, made by manufacturer Carbon.
While this technology is different from conventional 3D printing technologies, there are more improvements ahead. Currently, 3D printing at dental labs is only used for models and surgical guides for implant placements, but expect important changes in the next year or so – and expect even more Earth-shattering advancements in the years to come.
The near future
Carbon’s technology is a radical take on the 3D printing process.
“We are using light to cure UV-curable resins,” Elle Meyer, Director of Business Development, Medical Technologies at Carbon,ß says. “What's really unique about our technology is we have a window that is not only transparent to light, but also permeable to oxygen. And as a result of it being oxygen permeable, we have a dead zone at the surface of the window where polymerization is inhibited. It's really that dead zone that allows us to draw the parts out of the liquid without having a mechanical delamination step that you'd see with more conventional 3D printing approaches.
In the near term, experts expect the ability to 3D print final dental restorations in different colors.
“What I see coming down the line in the next six months to a year, is probably the finalization and wide adoption of 3D-printed restorations,” Chris Kabot, Dental Applications Specialist at EnvisionTEC, says. “Whether that is a final restoration or a temporary restoration. We're going to have a number of new shades that we're going to be able to print, and those shades won’t just be for temporary restorations.”
Mark Ferguson, General Manager at Vulcan Custom Dental, says hybrid manufacturing – a combination of both milling and printing – will help improve cases where high accuracy is important – like the creation of implants.
“You'll get the basic shape, whether it's laser-sintered or some other technology,” he says. “So, you'll print your part, but in places where you need higher accuracy, you would then have a jig or something else to transfer that part from the 3D printer to a milling machine. With 3D printing metals, you can get some more complex shapes that you would never get with milling. You could 3D print them and have a nicer surface for acrylic or porcelain application, but then still get the accuracy that you need for a perfect fit in the mouth.”
3D printing the final restoration will not only be easier, but will also be less expensive – costing about a dollar per printed tooth
“The cost it takes to mill is pretty high, because you have about 30 percent waste,” Kabot says. “When you print, not only is the material cheaper for raw material costs, but there's no waste associated with printing.”
Next: What will technology look like down the road?
3D printing solutions are comprised of two components – materials and printer technology. The technology is what's required to actually turn those materials into usable items. It comes down to the items that labs and doctors will require.
“There are a lot of new developments in 3D printing technologies that are interesting, but the materials component of that is just as exciting as printer hardware,” Gideon Balloch, Product Manager at Formlabs observes. “This is because, at the end of the day, 3D printing shouldn’t be a selling point in itself, even though lasers are exciting. Instead, we are focused on competing by using new materials to enable a broader range of applications, and outperforming other manufacturing methods based on final part quality, material properties and cost. That’s what makes a real difference to labs and doctors.”
Formlabs designs and manufactures powerful and accessible 3D printing systems such as the Form 2, an SLA desktop 3D printing system, popular with dentists.
For dental restorations, there are already tried and true materials that manufacturers strive to embrace. Justin Marks, CDT, Founder and CEO of 3D printing manufacturer Arfona, looks to new technologies to utilize those materials.
“If it hasn't already been digitized, manufacturers are working on a way to do that,” Marks observes. “Metal has been cast for centuries. There are ways of 3D printing it, and labs are either figuring it out for themselves or outsourcing the components that they can't do themselves. Same thing with polymers. There are technologies for 3D printing a lot of different plastics now that didn't exist before. And ceramics is one of the areas that is not being 3D printed right now. It can be milled, but it can't be printed, quite yet. Ceramic printing is pretty high on that list, and to be able to do that in multi-shaded, multicolored materials.”
Jeff Youngerman, CDT, Western Account Manager for Stratasys, expects that the ability to handle those materials in advanced ways will shape the future of 3D printing.
“Being able to multi-jet out materials, meaning we can change colors, we can change textures, we can do multi-prints, meaning multiple applications at one time, this is the future of 3D printing in the dental laboratory, as far as being productive, as far as fitting in to what the industry is looking for and needing,” he says. “There are going to be more metal printers out there, there are going to be more ceramic printers out there, there’ll certainly be more resin-based printers out there. It’s kind of a mish-mosh right now, because it’s kind of limited to the materials that are available. The science behind the printing technology will continue to advance – printers with multiple printheads and multiple nozzles within each print head.”
As applications become more advanced, like bioprinting, for example, the technology becomes more demanding.
“One of the problems, when you talk about bioprinting, is the vascularity within a structure,” Dr. Roger Narayan, Professor in the Joint Department of Biomedical Engineering at the University of North Carolina and North Carolina State University, explains. “You also have a question of how do you print cells at a fast enough rate in order to create large tissue? Those are issues in bioprinting hardware, in general. You need, basically, uniform feedstock materials with known properties. You need to have equipment with known parameters for processing equipment. You need to understand the short-term toxicity, the long term toxicity, the breakdown products associated with the 3D printed products. You have to reduce the equipment costs, reduce the input costs, you have to increase the throughput for these 3D printing technologies.”
And, to some degree, the all-digital workflow is an important component in 3D printing technology.
“We like to go model-free in a lot of our work, because it reduces turnaround time and costs,” Ed Peay, a CAD/CAM technician at Utah Valley Dental Laboratory says. “When we are milling e.Max or zirconia, many doctors have less seating time. We're not having to do a lot of extra layers to achieve the goal that we're currently doing with resin models.”
“I see a doctor taking a CBCT scan of a patient and then sending that file to Ed, along with a scan of the patient’s bone and tissue, for doing the restoration,” Jeff “JD” Henderson, Vice President/Lab Manager at Utah Valley Dental Lab, adds. “Ed matches those two things and then has a virtual replica of the patient’s mouth, enabling us to create a custom design unique to each patient. Because we have virtual patient models that mimic accurate movements, we can set up their occlusions and their bite, designing everything from a whole mouth to one tooth, ultimately enabling the patient to have a better restoration.”
The 3D printing market is opening up with more and more manufacturers offering their own printers. Given the influx of new technologies, Chris Frye, Digital Technology Solutions Sales Manager and Dental Channel Sales Manager at Whip Mix says the technologies, themselves, are not where the future of 3D printing lies.
“More and more low cost 3D printers are entering the market at what seems like every month,” he says. “You have certain patents expiring soon that will bring additional printing technologies to the market at presumably a lower cost than what they are being offered currently. The true future of the technology lies in the materials.”
Next: What the future holds for materials.
Materials are the other necessary component when looking at future 3D printing dental applications. Even currently used materials require advancement.
“There's interest also in trying to get new classes of feedstock materials,” Dr. Narayan observes. “There are companies looking at trying to increase use of ceramics for additive, but the problem with ceramics is, by their very nature, they're very brittle materials. People have long been able to create ceramic parts, but the challenge is now trying to make ceramic parts with the mechanical properties that you see in your conventionally prepared materials, and that's going to be a big challenge.”
“We see materials going in different directions, driven by the applications we want to enable with 3D printing,” Balloch says. “If you take the example of printing crowns or bridges as an application, the long term aim is direct printing permanent restorations, and we’re doing some materials development in that direction. Ceramics are one potential pathway, but this is highly dependent on quality and performance. We actually have an experimental ceramic resin that successfully prints on the Form 2, but we have focused that on other industries so far, because a dental ceramic would have to be much higher performance. So we are using that to learn more about ceramics in general, and use that knowledge to push ceramics to the level they’d need to be for dental.”
Like open CAD/CAM systems, Frye says that 3D printers must be able to work with non-proprietary materials.
“With the entrance of open material source printers (meaning printers that are ‘open’ or will print any suitable resin), such as the Asiga line of 3D printers, a lot of chemical companies are beginning to develop resins for the dental industry,” he says. “We currently have a few companies that have a material for 3D printing the provisional dental crown. This is the first step to 3D printing the final restoration. Although I don’t believe it will be a resin (a UV-curable photopolymer) material that we will print the final restoration in, the industry is well on its way. Currently there are companies working with 3D printing of ceramic material as well as a composite material that is a combination of titanium and zirconia that could most certainly lead to printing the final restoration.”
“There are a lot of options on the table,” Brian Ganey Business Development Manager, Life Sciences at Carbon adds. “The nice thing about our technology is that we are compatible with third-party resins that we have identified and believe are good stepping stones for us.”
While we look to innovators delivering those materials, governments have to be involved before those materials can come to market.
“I expect to see a huge broadening of offerings,” Dr. Ulrich Koops, Group Product Manager for Digital Fixed Prosthetics at Kulzer, says. “Few will though remain, because of the regulatory requirements that need to be fulfilled globally. In terms of applications for dental the maturity of materials for permanent restorations will increase, allowing much more automated results based on the high skills of digital dental technicians.”
At this point, however, manufacturers have a lot of balls to juggle in order to get these materials to market.
“Companies are still vying to figure out how to print the material and then for us to be able to do it at an extremely refined level,” Marks says. “Not only because of color and optical properties, but obviously because of the small sizes and resolutions and accuracies that we would require in the dental industry – not to mention the regulatory burden when it comes to registering those materials.”
Next: The emergence of bioprinting
Maybe one of the most compelling future 3D printing capabilities will be the ability to print body parts – whether that be a liver, a kidney or even a tooth.
Dr. David Hornbrook, DDS, a cosmetic dentist in San Diego, thinks there are a number of components that can help dental applications.
“The applications in dental would be dentin and enamel,” Dr. Hornbrook says. “If we could scan a preparation and print it out of dentin or enamel, we’re replacing a natural human tooth with a natural material. Second would be soft tissue, where we could do gingival grafts and we’d actually print tissue, rather than taking tissue from another part of the body. The third thing would be bone, where you could print bone to augment ridges for dentures or implants or to take a digital impression of an extraction site and have bone printed that would fit exactly into that extraction site. I think there are huge applications for that.”
Not surprisingly, the human body is a complex machine and bioprinting is still in its early stages.
“The people who work on bioprinting focus a lot on the liver,” Dr. Narayan says. “Because that is the focus of drug discovery studies. They look at the kidney because that is another organ that is another focus area for drug discovery studies. They look at the skin. I have colleagues, craniofacial surgeons, who are looking at products for cleft palates. You certainly do have the potential to make other sorts of products, like teeth or jaw bone or other types of tissue, but, for many of these bioprinting technologies, I also think the question is cell sourcing and cell quality, the use of growth factors. and many of these topics have not been standardized for bioprinted implantables. It's a lot easier to have a drug discovery product that is functional than to have an implantable that comes from a cell source that has growth factors incorporated into it and having that be suitable for implantation.”
The best material for dental applications, observes Henderson, is actual teeth.
“If I think about the perfect material, it would be anything that can mimic natural teeth,” Henderson says. “Usually, when there are material failures, there’s something out of the norm; it’s biologically not compatible, for example. I would expect that to be where everyone’s heading, but it feels a long, long way off.”
While commercially-printed biomaterial is not currently available EnvisionTEC offers three models of its 3D-Bioplotter to researchers.
“Our 3D-Bioplotter is the most researched bioprinter in the world,” Kabot says. “We have it in multiple research programs all over the world. It was just recently used to synthetically 3D print ovaries that were implanted into mice. They actually took and were able to facilitate fertility.
“We are also using our Bioplotter in dentistry, as well,” he continues. “A widely cited research publication used our Bioplotter at the University of Columbia to 3D print the first ever cementum structure. So they 3D printed this scaffold out of what we call protein-releasing scaffolding, they soaked this synthetic cementum structure in a stem cell solution, they then implanted this into the jaw of mouse, and we saw no rejection – complete osseointegration, and it's the first time that the periodontal ligament has actually recognized a foreign body and attached itself. This has massive, massive implications in dentistry. You could start thinking of implants as actually bioprinted. Instead of having a titanium screws and an abutment and then a crown that goes on top of that, what if we're able to get rid of that, entirely and just directly 3D print out a full tooth, root, crown and all, that's made out of the patient’s stem cells that has no rejection. That is the true future of 3D printing in dentistry where we start forgetting about implants – they become a thing of the past – and we actually start bio-growing peoples’ teeth. I think within the next decade we are going to see this become a reality.”
“It’s the old story: Once they broke the first seven-minute mile, then the six-minute mile then the five-minute mile,” Youngerman observes. “Once they have a start to it, then I believe they’ll be able to show more advancements. I think it’s very premature, but I think it’s realistic. When we talk about the future, absolutely we’ll be able to print those types of things.”
But for dental applications, bioprinting has a ways to go. For other organs, we’re much closer.
“Other markets are showing more advancement because we have different types of 3D printing technology, which opens the door for different materials,” Youngerman says. “We work within a very, very tight micron accuracy, FDA approvals, and things like that, that other industries are not a slave to.”
“It's for parts and pieces of humans that aren't under the strict tolerances of dental,” Ferguson adds. “For a liver, a millimeter’s not a mile, for a tooth, it is.”
Next: What will this mean for cost and prices?
Labs and doctors are, ultimately, businesses. So while these advances in 3D printing technology are interesting, to say the least, without some sort of return on investment, don't expect to see them in labs or doctor’s offices.
Kabot anticipates a reduction in overall cost and the overall time that it takes to produce dental applications.
“What we are going to start seeing, because we can print 3D models, restorations, any application that can be 3D printed, we can do for a lower cost than what's currently in the market,” Kabot observes.
Dr. Koops does not anticipate those cost reductions extending to the patient.
“The patient will not profit directly from the better economical results digital processes can deliver,” Dr. Koops says. “First of all, these digital processes need to be set up, brought to throughput and have investments amortized before we see a major decline in prices to the customer. Patients will thus profit in time and quality.
“Since the design competency for most dental appliances is at the dental technician, the revenue will remain shared between dentists and dental technicians,” he continues. “We have to keep in mind that most of the value generated in dental appliances to cure defects is done in designing the proper shape and appearance individually. Even though manufacturing processes and its materials play an essential role in how to achieve the results, it is always an individual part specially manufactured, that needs the great attention of the dentists and dental technicians to make it work well for the patient.”
Ferguson notes that because technologies improve and costs come down, the industry is at risk of introducing lower quality equipment, just for the sake of remaining competitive.
“The 3D printers that are out now that are lower-cost are getting a lot of praise for their accuracy and everything,” he observes. “It's amazing, to me, how cost has pushed the availability of 3D printers and has really pushed people to find it more acceptable. Hopefully we will see an increase in quality at that lower cost, and I think we will. The concern that I have is that people are looking at something affordable, and saying, ‘Yeah, it's affordable, but it's acceptable because it's affordable.’ But in my opinion, that shouldn't be the case. It should be acceptable because the quality is there, not just because it's affordable. Let's hope lower cost doesn't force people to accept lower quality.”
Whether or not that cost savings trickles down to the patient is a business decision, more than anything.
“If we are printing things out that are less expensive than what we're currently providing, essentially, those savings should get passed onto patient,” Kabot says. “But that big word ‘should’ should be highlighted and underscored, because at the end of the day, it's up to the doctor to decide what they want to charge the patient. If the doctor is all of a sudden getting a lab bill now that is significantly lower than before, are they going to pass those savings along?”
3D printing is an amazing technology, one that promises fantastic advances for labs and doctors, not only in the months to come, but in the years to follow.