BEGO USA Bets on EOS Technology Biting Big into Changing U.S. Dental Restoration Market
By Wiebke Jensen, Electro Optical Systems
Additive manufacturing is disrupting another traditional industrial technology - the fine art of dental restoration, which rescues damaged teeth with devices ranging from simple fillings created in the patient's mouth to crowns, bridgework and implants that are manufactured via multiple processes away from the dentist's office. Many restorations performed today still use lost-wax technology that has barely changed in 100 years. But this appears to be changing.
"With skyrocketing gold prices and pressure to find cost-effective methods for saving smiles, we've realized that our present product line supporting lost wax is probably going to be obsolete in 10 to 15 years," predicts Bill Oremus, president of Rhode Island-based BEGO USA. "The end of casting is approaching, as additive manufacturing alters the dental landscape."
Recognizing this, BEGO launched an initiative into on-site production of non-precious-alloy restorations with a direct metal laser sintering (DMLS) system it purchased in 2011 from EOS GmbH. Within a year of beginning to use the EOSINT M 270, BEGO was producing hundreds of restoration units a week that are fully dense and without porosity.
"Our customers simply send us any open STL file of a patient's mouth scan, and, after a file review step, we manufacture the coping in about 48 hours," Oremus says.
The laser sintering system holds a bed of powdered metal material and processes the crowns or bridges layer by layer. After a thin layer of the powder is applied, a focued laser beam solidifies it, and the powder bed drops by a fraction of a millimeter to begin the next layer. The DMLS system runs automatically, quickly and economically with accuracy of +/- 20 microns.
While the traditional casting process can produce about 20 dental frames per day, DMLS manufacturing is scalable to as many as 450 crowns and bridges in the same time period. "The restoration only needs some rubber-wheel finishing in the margins and it's ready for veneering with ceramics," Oremus says. "In the case of a bridge, the end-product doesn't need sectioning and just drops into place.
"The quality of the restorations is truly excellent, the surface structure of the copings is so much better, and the marginal integrity is phenomenal. We save cost and time."
In an industry where patient specificity is critical, these qualities are key. "If you were to put 10 long-span bridges through the old lost-wax technique, you would be looking at only 50-60 percent accuracy," Oremus says. "That's a lot of do-overs and incresed wait-time for the patient. using our EOS system today, we're getting a 90-95 percent success rate and saving time."
Since the EOS system can work with virtually any properly prepared metal powder, BEGO has patented its own high-performance chrome-cobalt-molyb-denum alloy, Wirobond C+. The material contains more than 20 percent chromium, which, during manufacturing, creates a passivity layer that prevents the release of free ions, ensuring high biocompatibility. "Whatever alloy we are working with, we find that EOS' machines are head-and-shoulders above others in terms of control of laser-beam size and effects on different restoration geometries and materials," Oremus says. The fact that laser sintering systems can be run with a wide variety of registered/validated materials is also of particular interest to the dental industry, which is always on the lookout for alloys with improved characteristics. "Durability and performance are key in restoration," he says. "The muscles of the jaw generate huge amounts of force on teeth and they have to withstand thermal expansion and contration."
Plus, DMLS uses less material than more-traditional manufacturing methods. "A major advantage is the cost-effectiveness of the build-up technique versus so many of the other subtractive techniques," says Ryan LeBrun, BEGO's CAD production manager. "With high-end metals, your profits are just ground away. There's almost no waste with additive manufacturing. We can filter any extra unused powder and reuse it on the next production run. We're able to pass our savings on to the laboratory and the technician to help give them a better profit picture."
What's more, says Oremus, other advances in the digitalization of dentistry are primed to support the acceptance of the technology. "The use of char-side mouth scanners will make CAD modeling incresingly common and futher drive the use of additive manufacturing in dentistry," he says.
For more information on EOS-Electro Optical Systems, visit eos.info/en. For more information about additive technologies in general, contact Tim Shinbara, Technical Director, AMT - The Association For Manufacturing Technology, at tshinbara@AMTonline.org or 703-827-5243.