A dental crown is produced by a method developed by researchers at the University of Texas at Dallas. The approach combines improved heat transfer with the use of porous graphite, which can reach temperatures in excess of 2,550 degrees Fahrenheit. Watch a short video of the technology in action by clicking the play button.
Researchers at the University of Texas at Dallas have developed a technology that enables same-day, 3D-printed dental restorations made of zirconia, the gold standard for permanent dental work.
The team is working to make the technology, which could be used for crowns, bridges, veneers and other restorations, commercially available with support from the National Science Foundation (NSF).
Dr Majid Minary (left) and mechanical engineering PhD student Mahdi Mosadegh describe the technology in the September print edition of the journal Ceramics International.
“We are excited to advance the commercialization of chairside 3D printed, all-ceramic zirconia permanent dental restorations,” he said. Dr. Majid Minarihis teacher mechanical engineering at Erik Jonsson School of Engineering and Computer Science. “Because crowns can be custom-printed for each patient on the same day, this approach offers greater customization, faster treatment and the convenience of obtaining a permanent restoration in a single visit.”
Dental crowns are covers that are placed over damaged or decayed teeth. They can also serve as abutments on a dental bridge, which replaces a missing tooth. 3D printed restorations have emerged as an option that offers better fit and color matching, as well as a more efficient manufacturing process that could reduce costs and waste. The 3D printed crowns currently available, however, are made of ceramic resins that are not as strong as zirconia.
And while same-day zirconia crowns are also available, they are not 3D printed. Rather, they are milled, a process that involves carving the crown from a block of zirconia. These zirconia restorations face challenges and limitations in design complexity and risks for microcracks during milling or sintering.
UT Dallas researchers and their colleagues have solved a challenge in producing 3D-printed zirconia restorations, significantly reducing the time required to process a zirconia restoration after 3D printing. The researchers explain their approach in the September print edition of the journal Ceramics International. The method will require clinical validation and regulatory approval before it can be commercialized.
After a zirconia crown is 3D printed, it must undergo two basic steps: debonding and sintering. In the debonding step, heat is gradually applied to burn off the resin that held the zirconia particles in place during printing. This process can take anywhere from 20 to 100 hours. Once the resin is removed, the crown undergoes sintering—a high-temperature firing process similar to kiln-fired clay—which fuses the zirconia particles together into a dense, hardened solid.
“The disconnection was the bottleneck in the process,” said Minary, corresponding author of the paper. “It has to be done very slowly. If you speed it up, the burning polymer turns into a gas, and if that gas can’t escape, the crown can crack or break. A debonding time of 20 to 100 hours is not practical for the same-day dental service. As a result, permanent 3D-printed zirconia restorations are not yet commercially available.”
A finished dental crown created by UT Dallas researchers’ technology.
The team’s technology cuts release time to less than 30 minutes—a breakthrough that could make same-day permanent dental restorations possible. Their approach combines improved heat transfer with the use of porous graphite, which can reach temperatures in excess of 2,550 degrees Fahrenheit. Felt covers the 3D-printed restoration, allowing the gas released from the resin to escape, while a vacuum system simultaneously removes the gas.
“The combination of all these features is what makes it work,” Minary said. “With our technology, if a practitioner wanted to provide a chairside 3D printed zirconia crown, they could provide it to a patient in just a few hours.”
The UT Dallas team led by Minary, in collaboration with the Pan-AM Dental Laboratory, recently received a $550,000 award (grant 2431684) through NSF’s Partnerships for Innovation – Technology Translation project to support technology commercialization.
The commercialization project also includes 3DCeram Sinto Inc. in Grand Ledge, Michigan. and Dr. Amirali Zandinejad, a prosthodontist in Arlington, Texas, and former associate professor at Texas A&M University College of Dentistry.
Other collaborators affiliated with UT Dallas include Mahdi Mosadegh, first author and a mechanical engineering doctoral student. Moein Khakzad PhD’25; chemistry PhD student Zahra Sepasi. mechanical engineering graduate student Kalyan Nandigama. and Dr. Golden Kumarassociate professor of mechanical engineering.
In addition to NSF, research on the work was also supported by the US Air Force Office of Scientific Research.
