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Toothbrush Takeover: Nanobot Swarm that Can Brush, Floss, and Rinse Teeth

An interdisciplinary team of researchers at the University of Pennsylvania has developed a robotic swarm of iron oxide nanoparticles that can remove plaque from teeth via brushing and flossing, as well as kill pathogens due to its ability to catalyse the formation of free radicals from hydrogen peroxide for disinfection purposes.

A visual representation of the robotic swam of magnetic iron oxide nanoparticles that can form bristles to remove plaque from teeth. The particles also catalyse the formation of free radicals from carbon dioxide, for the elimination of decay-causing microbes form tooth surfaces. Photo Credit: Minjun Oh/Penn Dental Medicine

A nanobot swarm able to perform all the functions of a toothbrush and more has been developed by an interdisciplinary team of researchers at the University of Pennsylvania. It is able to scrub biofims off teeth surfaces, rinse, floss in between teeth surfaces, and holds promise to help those who have lost the ability to maintain a high standard of dental hygiene on their own.

This project was a successful collaboration between Penn Dental Medicine and Penn Engineering. The dental research group, led by Professor Hyun (Michel) Koo, a professor in the Department of Orthodontics and Divisions of Community Oral Health and Paediatric Dentistry at Penn’s School of Dental Medicine, was studying the antimicrobial effects and ability of the free radicals produced by iron oxide nanoparticles to break down dental biofilms while the engineering research group, led by Edward Steager, a senior research investigator in Penn’s School of Engineering and Applied Science, tried to find applications of microrobots comprising iron oxide nanoparticles steered by magnetic fields.

This nanobot swarm comprises nano-sized particles of iron oxide that are capable of catalytic action and have magnetic properties. With a magnetic field, the researchers could manipulate the overall shape of the cluster of nanoparticles to form bristle-like structures suitable for removing plaque from broader teeth surfaces. These nanoparticles could also be manipulated into long, thin string-like structures resembling dental floss, suitable for removing food in between teeth. Furthermore, the catalytic action of the nanoparticles causes them to produce antimicrobial substances that keep oral bacteria at bay, making them extremely capable of maintaining high standards of dental hygiene.

The researchers studied the cleaning effects of their nanobots on synthetic and real human teeth and found that their creation was successful in removing the sticky layers of plaque that may result in cavities and gingivitis (gum inflammation).

Routine oral care is cumbersome and can pose challenges for many people, especially those who have a hard time cleaning their teeth” said Professor Koo, corresponding author of the study. “You have to brush your teeth, then floss your teeth, then rinse your mouth it’s a manual, multi-step process.”

According to the other main author of the study, Edward Steager, the system may be programmed to assemble itself into the correct structures and carry out the relevant dental hygiene maintenance practices, making their creation extremely promising in terms of convenience and utility for those unable to properly maintain dental hygiene.

To examine the effectiveness of the microrobots in removing dental biofilm from teeth surfaces, the research team first designed the nanobot movements by using them to move on a textured chunk of material resembling a tooth surface. Then, they tested the nanobot’s ability to mould and fit into the contours of the gumline, interdental surfaces, as well as exposed tooth surfaces on realistic and synthetic tooth models. Final testing was also done on models with accurately placed, real human teeth.

On all the tested surfaces, the nanoparticles were able to remove the biofilm plaque adhesions from the tested surfaces, as well as kill all the common pathogens that the researchers tested for. Despite their efficacy, they were still found to be gentle enough to not have any adverse effects on the sensitive gum tissue.

By making controlled variations of the magnetic field, the researchers were able to regulate the stiffness and structure of the nanoparticle bristles as well as their movements. This allowed them to clean teeth with sufficiently stiff bristles and strong movements that allowed for the complete removal of plaque and pathogens, without injuring the teeth and gums.

As the system can produce a wide range of structures with multiple ranges of movement, it is highly versatile and may have other applications other than maintaining dental hygiene in a clinical setting. The researchers also note that its ability to mould to the unique topology of a patient’s teeth might be useful for other applications, which are still under development.

In the future, the team hopes to improve their patients’ quality of life with their novel technology, especially the disabled or elderly who may have limited dexterity in maintaining a good standard of dental hygiene. They also hope that their creation will help push the frontiers of oral care and lead the way for the development of more innovative approaches for the maintenance of oral hygiene. [APBN]

Source: Oh et al. (2022). Surface Topography-Adaptive Robotic Superstructures for Biofilm Removal and Pathogen Detection on Human Teeth. ACS Nano.