Shapeshifting microbot swarms used to brush teeth ‘hands-free’ by scientists

New shapeshifting robotic microswarms can clean off sticky biofilm from teeth in an advance that could lead to new hands-free technology for an all-in-one toothbrush, rinse and dental floss, said researchers.

The novel hands-free system could automate the treatment and removal of tooth-decay-causing bacteria and dental plaque, showed a proof-of-concept study published last week in the journal ACS Nano.

These microbots, made of ultra-small iron-oxide nanoparticles, have both catalytic and magnetic activity and could be directed to form bristle-like structures that sweep away dental plaque from the broad surfaces of teeth, said researchers at the University of Pennsylvania in the US.

The robotic microswarms could also be directed to form elongated strings that would slip between teeth like floss.

In both these formations, a catalytic reaction would drive the tiny particles to produce antimicrobials that kill harmful oral bacteria on site.

“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,” said Hyun (Michel) Koo, a co-author of the study from the University of Pennsylvania.

Researchers said the nanoparticles could be shaped and controlled with magnetic fields in “surprising ways”.

“We form bristles that can extend, sweep and even transfer back and forth across a space, much like flossing. The way it works is similar to how a robotic arm might reach out and clean a surface. The system can be programmed to do the nanoparticle assembly and motion control automatically,” said Edward Steager, another study co-author.

The microbot swarms can adapt to different surfaces, adjusting to “all the nooks and crannies” in the oral cavity and even work on misaligned teeth.

In the research, scientists optimised the motions of the microrobots on a small slab of tooth-like material, also testing them on interdental surfaces and the gumline using 3D-printed tooth models based on scans of real human teeth.

Researchers also trialled the microbots on real human teeth that were mounted in such a way as to mimic the position of teeth in the oral cavity.

They said the microbot system could effectively eliminate biofilms, clearing them of all detectable pathogens.

In further studies, scientists hope to optimise the robots’ motions and are considering different means of delivering the microrobots through mouth-fitting devices.

“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,” Dr Koo said.