Micro-robots can help dentists remove plaque: Study

Scientists have developed micro-robots which can break apart and remove dental biofilm or plaque from teeth, thereby significantly reducing the burden on dentists.

A visit to the dentist typically involves time-consuming and sometimes unpleasant scraping with mechanical tools to remove plaque from teeth. A team of engineers, dentists, and biologists developed a microscopic robotic cleaning crew with two types of robotic systems -- one designed to work on surfaces and the other to operate inside confined spaces.

Scientists showed that robots with catalytic activity could destroy biofilms, sticky amalgamations of bacteria enmeshed in a protective scaffolding.

Such robotic biofilm-removal systems could be valuable in a wide range of potential applications, from keeping water pipes and catheters clean to reducing the risk of tooth decay, endodontic infections, and implant contamination.

"This was a truly synergistic and multidisciplinary interaction. We're leveraging the expertise of microbiologists and clinician-scientists as well as engineers to design the best microbial eradication system possible. This is important to other biomedical fields facing drug-resistant biofilms as we approach a post-antibiotic era," said Koo, lead author of the study published in Journal of Science Robotics.

"Treating biofilms that occur on teeth requires a great deal of manual labour, both on the part of the consumer and the professional. We hope to improve treatment options as well as reduce the difficulty of care," added Steager, co-author of the study.

Biofilms can arise on biological surfaces, such as on a tooth or in a joint or on objects like water pipes, implants, or catheters.

Wherever biofilms form, they are notoriously difficult to remove, as the sticky matrix that holds the bacteria provides protection from antimicrobial agents.

The engineers control the movement of these robots using a magnetic field, allowing a tether-free way to steer them.

Together, the cross-school team designed, optimised, and tested two types of robotic systems, which the group calls catalytic antimicrobial robots, or CARs, capable of degrading and removing biofilms.

The first involves suspending iron-oxide nanoparticles in a solution, which can then be directed by magnets to remove biofilms on a surface in a plow-like manner.

The second platform entails embedding the nanoparticles into gel moulds in three-dimensional shapes. These were used to target and destroy biofilms clogging enclosed tubes.

Both types of CARs effectively killed bacteria, broke down the matrix that surrounds them, and removed the debris with high precision. After testing the robots on biofilms growing on either a flat glass surface or enclosed glass tubes, the researchers tried out a more clinically relevant application: Removing biofilm from hard-to-reach parts of a human tooth.

The CARs were able to degrade and remove bacterial biofilms not just from a tooth surface but from one of the most difficult-to-access parts of a tooth, the isthmus, a narrow corridor between root canals where biofilms commonly grow.

"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. These robots can do all three at once very effectively, leaving no trace of biofilm whatsoever," said Koo.