Scientists Develop Antimicrobial Plastic for 3-D Printing Teeth

A woman displays 3-D printed teeth and jaw implants at the 2013 London 3D Printshow. Dutch scientists have developed an antimicrobial plastic.  Piero Cruciatti/Demotix/Corbis
A woman displays 3-D printed teeth and jaw implants at the 2013 London 3D Printshow. Dutch scientists have developed an antimicrobial plastic. Piero Cruciatti/Demotix/Corbis

The advent of 3-D printers — which spray layers of plastic or other materials to build objects — seems to be on the verge of revolutionizing everything from aircraft manufacturing and house-building to the pastry menu at cafes. So it's not that surprising that it soon could revolutionize your dental care, as well.

A team of researchers at the University of Groningen in the Netherlands have developed a new plastic with antimicrobial properties, which could be used with a 3-D printer to make crowns, veneers, orthodontic braces and presumably even dental implants. Unlike your real teeth and existing dental work, the ones fashioned from the new material would resist damage from the bacteria that continually lurks in your mouth.

A molar replacement tooth Dutch scientists created out of antimicrobial plastic using a 3-D printer.
Andreas Herrmann

Andreas Herrmann, a professor in the university's Zernike Institute for Advanced Materials, created the plastic with colleagues by embedding bacteria-killing quaternary ammonium salts in an existing polymer resin used in dental labs.The salts contain positively-charged particles that disrupt negatively-charged bacterial membranes, causing them to break. (Fortunately, the salts have no any effect on the human body's own cells.) 

When that material is put into a 3-D printer and hardened with ultraviolet light, it can be used to create various stuff that dentists can install in your mouth.

As a test, the researchers printed dental implants and braces, and then painted them with a disgusting mix of human saliva and Streptococcus mutans, the bacteria that causes tooth decay. Tests showed that the antimicrobial plastic killed 99 percent of the bacteria, compared to a control group of plastic without the salts, in which 99 percent of the microbes survived.

Get a Plastic Grill

For transhumanists, who dream of altering and augmenting their bodies with technology to become Homo sapiens 2.0, this all might seem like an invitation to have their teeth extracted and replaced with superior man-made ones. But in an email, Herrmann says that the researchers don't have that extreme in mind. Instead, they're looking for a way to help you keep the teeth that you have.

"The technology will be used to 3-D print crowns or veneers," he says. "An even more immediate application is [in] orthodontics, where we plan to fabricate transparent retainers."

In any case, it'll be a while before 3-D-printed antimicrobial plastic anything shows up in your dentist's office.

"We will perform further toxicity testing and we need to evaluate how the properties develop upon long term exposition to an environment like the oral cavity," says Herrmann. "So far, we just tested performance during six days exposed to saliva. But 3-D printed objects should stay in the mouth for much longer — months and probably years — depending on the application. Moreover, we need to check what happens when we bring it in touch with toothpaste or mouthwash. Finally, we will perform clinical trials with a selected group of patients."

If all that goes well, and the material gets the required approval by the U.S. Food and Drug Administration, you could have 3-D-printed microbial plastic in your mouth in four to seven years, according to Herman.

But for Now ...

In the meantime, though, U.S. dental labs already are starting to utilize 3-D printing. Bennett Napier, executive director of the National Association of Dental Laboratories, says that about 40 percent of the nation's big labs already have a 3-D printer. "They're using them primarily for models, and to cast gold crown substructures," he says. "It's in the early-adoption stage."

While dental labs aren't yet printing crowns or implants on a regular basis, apparently there's at least one dentist who's experimenting with using a 3-D printer. In 2014 Harvard Business Review article, Business Innovation Factory founder Saul Kaplan as his dentist made a crown for him on a CNC milling machine, a variation on 3-D printing in which a digital scan of an object is used to carve a replica from a block of raw material.

Joseph DeSimone, CEO of the 3-D printing company Carbon3-D, predicted last year in a TED talk that advances in the speed of 3-D printing soon would enable dentists to print a new tooth for you in minutes, while you waited in the chair. While acknowledging that super-fast crowns and implants are at least a theoretical possibility, Napier says that the typical turnaround is more likely to be in the hours, because of the need to carefully design and test a product that you're going to depend upon for decades.