Shapeshifting Microrobots Can Brush and Floss Teeth

 by Ashnah Elanchcheliyan

In the future, an automated process for rinsing, brushing, and flossing teeth could be achieved through the use of a robotic microswarm. A team of experts from various fields, at the University of Pennsylvania, have created this technology, utilising a magnetic field to guide microrobots (made of iron oxide nanoparticles) into formations resembling antimicrobial bristles and floss. It's a system that could be particularly valuable for those who lack the manual dexterity to clean their teeth effectively themselves.

The building blocks of these microrobots are iron oxide nanoparticles that have both catalytic and magnetic activity. By employing a magnetic field, scientists can guide their movement and arrangement, shaping them into either bristle-like structures for sweeping away dental plaque from broad tooth surfaces or elongated strings resembling dental floss for interdental cleaning. In both scenarios, a catalytic reaction prompts the nanoparticles to generate on-the-spot antimicrobials, effectively eliminating harmful oral bacteria at the source. Tests conducted with this system on mock and actual human teeth revealed that the robotic assemblies can adapt to a range of shapes, effectively eliminating the presence of adhesive biofilms that contribute to cavities and gum disease.

Hyun Koo, a professor in the Department of Orthodontics at Penn’s School of Dental Medicine, says “Routine oral care is cumbersome and can pose challenges for many people, especially those who have a hard time cleaning their teeth. You have to brush your teeth, then floss your teeth, then rinse your mouth; it's a manual, multi-step process. The big innovation here is that the robotics system can do all three in a single, hands-free, automated way”. Nanoparticles can be manipulated and directed using magnetic fields in unexpected ways. It can create bristles that can extend, sweep, and perform similar movements done when flossing. It works similar to how a robotic arm might extend and clean a surface. The system can be programmed to automatically do the nanoparticle assembly and motion control. “It doesn't matter if you have straight teeth or misaligned teeth, it will adapt to different surfaces,” says Koo. “The system can adjust to all the nooks and crannies in the oral cavity”. 

The system is entirely programmable: the team's roboticists and engineers used variations in the magnetic field to precisely tune the motions of the microrobots as well as control bristle stiffness and length.The study revealed that the bristle tips could be engineered to be sufficiently firm for biofilm removal while maintaining a softness that prevents damage to the gums. Professor Koo stated that “we have technology that is equal to or more effective as brushing and flossing your teeth but doesn't require manual dexterity. We'd love to see this helping the geriatric population and people with disabilities. We believe it will disrupt current modalities and majorly advance oral health care”.