Researchers in the US have developed a way to 3D print permanent zirconia dental restorations in a matter of hours, opening the door to same-day treatments that previously required multiple visits.
Zirconia is widely regarded as the gold standard for dental restorations because of its strength, durability, and natural appearance. Until now, that level of quality has not been possible with true 3D printing on a same-day timeline.
Existing same-day printed crowns are typically made from ceramic resins, which are easier to process but lack the long-term strength of zirconia.
Zirconia crowns are already available for same-day use, but they are produced through milling rather than 3D printing. This process involves shaping the crown from a solid block of zirconia. While effective, milling can limit design flexibility and may introduce microcracks during production.
To overcome these limitations, the research team developed a method that significantly shortens the processing time required after a zirconia restoration is 3D-printed, publishing their findings in Ceramics International.
After a zirconia crown is printed, it must go through two essential steps: debinding and sintering. During debinding, heat is gradually applied to remove the resin that binds the zirconia particles during printing. This stage typically takes between 20 and 100 hours. Once the resin is eliminated, the crown undergoes sintering, a high-temperature process similar to firing clay in a kiln, which fuses the particles into a dense and durable structure.
“Debinding has been the bottleneck in the process,” Dr Majid Minary said.
“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 technique reduces debinding time to less than 30 minutes, making same-day treatment more feasible. The process uses improved heat transfer along with porous graphite felt capable of reaching temperatures above 2550 degrees Fahrenheit. The felt surrounds the printed crown, allowing gases released during resin removal to escape, while a vacuum system removes those gases.
“The combination of all of these features is what makes it work,” Dr Minary said.
