3D printed teeth to keep your mouths germ-free

Lost a tooth? Soon your dentist could print you another — and it’ll help keep your mouth clean, too.

Getting fitted for a false tooth or other dental treatment tends to involve a mouthful of foul-tasting gunk and plaster casts. But now dentists are moving to high-tech digital scanning and 3D printing. That switch opens the door to more advanced materials that could improve oral hygiene.

Andreas Herrmann of the University of Groningen in the Netherlands has developed an antimicrobial plastic, allowing them to 3D print teeth that also kill bacteria. It’s an important issue, say the team, because bacterial damage to existing implants costs patients millions of dollars in the US alone.

The team embedded antimicrobial quaternary ammonium salts inside existing dental resin polymers. The salts are positively charged and so disrupt the negatively-charged bacterial membranes, causing them to burst and die.

“The material can kill bacteria on contact, but on the other hand it’s not harmful to human cells,” says Hermann. Then they put this mix in a 3D printer, hardened it with VV light and printed out a range of dental objects such as replacement teeth. To test its antimicrobial properties, they coated samples of the material in mix of saliva and Streptococcus mutans, the bacterium that causes tooth decay. They found the material killed over 99 per cent of the bacteria, compared to less than one per cent for a control sample without the added salts.

Further tests will have to be done before the material can be rolled out to patients, as the team only left the samples in the saliva and bacteria mix for six days.

“For clinical uses we need to extend this, and investigate the compatibility with toothpaste,” says Herrmann.

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