The only sensation worse than the sound of nails on a chalkboard might be the feeling of dental tools scraping plaque off of your teeth. Luckily, a team of engineers, dentists, and biologists from the University of Pennsylvania have designed an army of plaque-busting micro-robots who might make your next dentist visit a bit more bearable — or at least more exciting.
Biofilm Be Gone
If you've ever run your tongue over teeth and thought, "Ew, I should really brush my teeth more often," you're probably feeling a sticky film called plaque. Plaque is a mix of proteins, sugars, and bacteria that's perfectly normal but can contribute to bad breath and make your teeth appear yellow. The bacteria especially can cause dental woes like cavities and gingivitis.
So how do you get rid of it? The easy answer is to brush your teeth at least twice a day and floss regularly to get to the hard-to-reach parts. However, even people with excellent oral hygiene habits should visit the dentist twice a year for a proper cleaning (though the "every six months rule" may be a myth).
Plaque is what's known as a biofilm, which is especially difficult to remove. The bacteria is held together in a tight matrix that's impervious to antimicrobial agents, so even top-of-the-line toothpaste can't completely eradicate the film on your teeth. That's bad news because once plaque has the chance to hang around for a while, it mineralizes into tartar: a hard yellow or brown gunk that can only be removed by a professional. If it feels like the dentist is scraping hard enough to make your gums bleed, they're probably just trying to chip away at that pesky tartar.
Enter Teeth-Cleaning Robots
To make your dentist's job a little easier, the UPenn team developed a "microscopic robotic cleaning crew" that can destroy plaque and other biofilms. The catalytic antimicrobial robots, or CARs, use iron oxide-containing nanoparticles that can bind to biofilms and set off a chemical reaction that kills the bacteria within them. The CARs' movement is controlled by a magnetic field, which allows engineers to steer the micro-robots as they target and clean up the bacteria.
The team designed two types of robot systems: one that uses a nanoparticle solution to clean surfaces and another that's 3D molded for fitting into tight spaces. The surface-cleaning system can plow through large areas or precisely target specific surface-level zones. The 3D-molded system can be designed to get down into the trickier areas. It was even able to remove biofilms from the isthmus, the skinny tube that connects one root canal to the next and is one of the hardest-to-reach parts of a human tooth.
In both cases, the CAR was able to target, destroy, and remove the debris. Removing the debris is especially important to minimize the chance of the biofilm growing back, co-lead researcher Hyun (Michel) Koo said.
"Existing treatments for biofilms are ineffective because they are incapable of simultaneously degrading the protective matrix, killing the embedded bacteria, and physically removing the biodegraded products," Koo said. "These robots can do all three at once very effectively, leaving no trace of biofilm whatsoever."
This innovation, which was published in the journal Science Robotics, has practical implications for keeping water pipes and catheters clean as well. Koo said the technology is also valuable in other biomedical fields as a way to address drug-resistant biofilms in the "post-antibiotic era."Source:web[/font]