The rapid evolution of 3-D printing technology in the dental industry will soon expand beyond simply creating crowns or dentures to incorporate chemicals that fight the bacteria that cause tooth decay and infection in the first place.

While it's still early in the game, researchers from the University of Groningen in the Netherlands have developed an antimicrobial plastic infused with quaternary ammonium salts that can eventually be used with 3-D printers to manufacture a variety of bacteria-zapping dental appliances within minutes, right in a dentist’s office.

In a study published in the scientific journal Advanced Functional Materials, the research team said it printed out two sets of replacement teeth — one with the ammonium salts mixed into the dental resin and the other without.

They found that after swiping both sets of teeth with the bacteria Streptococcus mutans, 99 percent of the bacteria was eliminated from the treated teeth while almost all of the bacteria remained on the control set.

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Good vs. Bad Bacteria

This combination of digital prowess combined with the added promise of longer-lasting and healthier teeth does raise an important question: Is eradicating all this bacteria from patients’ mouths such a great idea?

Officials at the American Dental Association (ADA) told Healthline that some colonization of bacteria is actually necessary for oral health. Without neutral or helpful bacteria, there's a chance patients' mouths could be colonized by other harmful organisms.

However, the ADA says that there's no reason, thus far, to think that dental restorations made from this 3-D printable resin will kill all the bacteria. After all, there are hundreds of species of bacteria in the human mouth.

"Given that the material works on contact, it is likely that teeth or fillings made from the material would only kill bacteria in a limited radius," ADA officials said. "Whether teeth or fillings made from this material could have any effect on other bacterial strains, or even function in a real human mouth, has not yet been determined."

The next step will be more extensive testing on the treated teeth to see how they hold up under longer periods of exposure to saliva, toothpaste, and other variables.

Once these "enhanced" dental appliances pass muster in the lab and hold up to the rigors of clinical trials in patients' mouths, they will become the latest innovation for an industry that has enthusiastically embraced 3-D printing and digital technology.

For decades, patients in need of a crown, a bridge, or dentures had an impression made during their first appointment. That impression was then sent out to the lab to create a plaster stone model from which the new crown or tooth was created. This would take a couple days or a couple weeks.

At the second appointment, the patient had the new tooth or crown installed. The dentist then shaved and customized some of the rough or imprecise edges, or grooves to make the new tooth fit comfortably.

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Digital Dentistry

With 3-D printers, a patient’s mouth is now digitally scanned by a wand that stores the file on a computer. This image is then manipulated using CAD software to precisely measure and design the new tooth.

The file is then sent to the 3-D printer where the tooth can be manufactured in minutes, allowing the patient to complete the procedure in one office visit.

Those digital files can be stored onsite or hosted in the cloud, keeping a patient's dental history a click away and eliminating the need to store thousands of plaster molds in offices and labs around the world.

SmarTech Markets Publishing, a Virginia-based market research and analysis firm for the 3-D printing and additive manufacturer sector, predicts that consumption of polymers by the 3-D printing industry will surge to more than $4.3 billion by 2023.

"What began as a more efficient way to manufacture dental crowns and bridges through printed lost wax casting patterns has moved well beyond that today," said Scott Dunham, vice president of research at SmarTech Markets.

"Because dental treatments can be made digitally with the absolute best accuracy using 3-D printed casting patterns or directly 3-D printed components, the fit and finish of the in-mouth solution is unmatched by traditional methods," he said.

In the years ahead, as more sophisticated dental products and appliances come to the market, Dunham said dentists will integrate processes into their own practices that traditionally have been sent out to labs, dramatically reducing the total time of treatment for patients.

"The result to patients is much higher quality of care and, typically, fewer visits to the dentist," he said.