- Researchers have found a way to slash the processing time for 3D-printed zirconia crowns from as much as 100 hours to under 30 minutes. The advance could eventually let dentists print strong, customized permanent crowns for patients within a single appointment.
Researchers at the University of Texas at Dallas have developed a technology that could make it possible for dentists to produce permanent 3D-printed zirconia restorations in a single day. Zirconia is considered the gold-standard material for permanent dental work because of its strength and durability.
With support from the National Science Foundation (NSF), the researchers are now working toward commercializing the technology for use in crowns, bridges, veneers and other dental restorations.
“We are excited to be advancing the commercialization of chair-side 3D-printed, all-ceramic zirconia permanent dental restorations,” said Dr. Majid Minary, professor of mechanical engineering in the Erik Jonsson School of Engineering and Computer Science. “Because the crowns can be custom-printed for each patient on the same day, this approach offers greater personalization, faster treatment and the convenience of receiving a permanent restoration in a single visit.”
Why Zirconia Crowns Are Difficult to 3D Print Quickly
Dental crowns are protective caps placed over teeth that have been damaged or affected by decay. Crowns can also be used to support a dental bridge, which replaces a missing tooth.
3D-printed dental restorations have become an increasingly attractive option because they can be customized more precisely and matched to a patient’s tooth color. The manufacturing process can also be more efficient, potentially reducing both costs and material waste. However, same-day 3D-printed crowns currently available are generally made from ceramic resins, which do not have the strength of zirconia.
Same-day zirconia crowns are already offered in some dental practices, but they are typically produced by milling rather than 3D printing. Milling requires carving the restoration from a solid block of zirconia. That approach can restrict the complexity of possible designs and carries a risk of micro-cracking during milling or sintering.
UT Dallas researchers and their collaborators have now addressed one of the biggest obstacles to producing zirconia restorations with 3D printing. Their method dramatically shortens the processing required after a restoration comes out of the printer.
The researchers described the technique in the journal Ceramics International. Before it could become commercially available, the method would still need clinical validation and regulatory approval.
Cutting a 20 to 100 Hour Process to Minutes
Once a zirconia crown has been 3D-printed, it must pass through two important stages called debinding and sintering.
During debinding, the crown is slowly heated to remove the resin that holds the zirconia particles together during printing. Traditionally, that step can require anywhere from 20 to 100 hours. After the resin has been eliminated, the crown is sintered. This high-temperature firing process works somewhat like baking clay in a kiln, causing the zirconia particles to fuse together and form a dense, hardened material.
“Debinding has been the bottleneck in the process,” said Minary, corresponding author of the article. “It must be done very slowly. If you speed it up, the polymer being burned off turns into gas, and if that gas cannot escape, the crown may crack or fracture. A debinding time of 20 to 100 hours is not practical for same-day dental service. As a result, 3D-printed permanent zirconia restorations are not yet commercially available.”
The new UT Dallas technology cuts the debinding stage to less than 30 minutes, potentially removing one of the main barriers to same-day permanent 3D printed dental restorations.
The system combines improved heat transfer with porous graphite felt that can reach temperatures above 2,550 degrees Fahrenheit. The felt surrounds the 3D-printed restoration and gives gases released by the resin a way to escape. At the same time, a vacuum system removes those gases from the surrounding area.
“The combination of all of these features is what makes it work,” Minary said. “With our technology, if a practitioner wants to offer a 3D-printed zirconia crown chair-side, they could provide it to a patient within just a few hours.”
Moving Toward Same-Day Commercial Dentistry
The UT Dallas team led by Minary is now working with Pan-AM Dental Laboratory to move the technology toward commercialization. The collaboration recently received a $550,000 award (grant 2431684) through the NSF’s Partnerships for Innovation — Technology Translation project.
The commercialization effort also includes 3DCeram Sinto Inc. in Grand Ledge, Michigan; and Dr. Amirali Zandinejad, a prosthodontist in Arlington, Texas, and former associate professor at the Texas A&M University College of Dentistry
Other UT Dallas-affiliated contributors include Mahdi Mosadegh, first author and mechanical engineering doctoral student; Moein Khakzad PhD’25; chemistry doctoral student Zahra Sepasi; mechanical engineering graduate student Kalyan Nandigama; and Dr. Golden Kumar, associate professor of mechanical engineering.
In addition to the NSF, the research in the paper was also supported by the U.S. Air Force Office of Scientific Research.
Source: University of Texas at Dallas
