Tag Archives: tooth decay

An army of microrobots can wipe out dental plaque

A sometimes unpleasant scraping with mechanical tools to remove plaque from teeth. What if, instead, a dentist could deploy a small army of tiny robots to precisely and non-invasively remove that buildup? A team of engineers, dentists, and biologists from the University of Pennsylvania 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—the scientists showed that robots with catalytic activity could ably 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.

The work, published in Science Robotics, was led by Hyun (Michel) Kooof the School of Dental Medicine and Edward Steager of the School of Engineering and Applied Science.

With a precise, controlled movement, microrobots cleared a glass plate of a biofilm, as shown in this time-lapse image

This was a truly synergistic and multidisciplinary interaction,” says Koo. “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.

Treating biofilms that occur on teeth requires a great deal of manual labor, both on the part of the consumer and the professional,” adds Steager. “We hope to improve treatment options as well as reduce the difficulty of care.”

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.

In previous work, Koo and colleagues have made headway at breaking down the biofilm matrix with a variety of outside-the-box methods. One strategy has been to employ iron-oxide-containing nanoparticles that work catalytically, activating hydrogen peroxide to release free radicals that can kill bacteria and destroy biofilms in a targeted fashion.

Serendipitously, the Penn Dental Medicine team found that groups at Penn Engineering led by Steager, Vijay Kumar, and Kathleen Stebe were working with a robotic platform that used very similar iron-oxide nanoparticles as building blocks for microrobots. 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, optimized, 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 molds in three-dimensional shapes. These were used to target and destroy biofilms clogging enclosed tubes.

Source: https://penntoday.upenn.edu/

How To Treat Oral Plaque Without Drugs

When the good and bad bacteria in our mouth become imbalanced, the bad bacteria form a biofilm (aka plaque), which can cause cavities, and if left untreated over time, can lead to cardiovascular and other inflammatory diseases like diabetes and bacterial pneumonia.

A team of researchers from the University of Illinois has recently devised a practical nanotechnology-based method for detecting and treating the harmful bacteria that cause plaque and lead to tooth decay and other detrimental conditions.

Oral plaque is invisible to the eye so dentists currently visualize it with disclosing agents, which they administer to patients in the form of a dissolvable tablet or brush-on swab. While useful in helping patients see the extent of their plaque, these methods are unable to identify the difference between good and bad bacteria.

In this illustration, nanoparticles attach to or are taken up by the bacteria cells. Pan and his students are the first group to demonstrate that early detection of dental plaque in the clinic is possible using the regular intraoral X-ray machine which can seek out harmful bacteria populations.

Presently in the clinic, detection of dental plaque is highly subjective and only depends on the dentist’s visual evaluation,” said Bioengineering Associate Professor Dipanjan Pan, head of the research team. “We have demonstrated for the first time that early detection of dental plaque in the clinic is possible using the regular intraoral X-ray machine which can seek out harmful bacteria populations.

In order to accomplish this, Fatemeh Ostadhossein, a Bioengineering graduate student in Pan’s group, developed a plaque detection probe that works in conjunction with common X-ray technology and which is capable of finding specific harmful bacteria known as Streptococcus mutans (S. mutans) in a complex biofilm network. Additionally, they also demonstrated that by tweaking the chemical composition of the probe, it can be used to target and destroy the S. mutans bacteria.

The probe is comprised of nanoparticles made of hafnium oxide (HfO2), a non-toxic metal that is currently under clinical trial for internal use in humans. In their study, the team demonstrated the efficacy of the probe to identify biochemical markers present at the surface of the bacterial biofilm and simultaneously destroy S. mutans. They conducted their study on Sprague Dawley rats.

In practice, Pan envisions a dentist applying the probe on the patient’s teeth and using the X-ray machine to accurately visualize the extent of the biofilm plaque. If the plaque is deemed severe, then the dentist would follow up with the administering of the therapeutic HfO2 nanoparticles in the form of a dental paste.

In their study, the team compared the therapeutic ability of their nanoparticles with Chlorhexidine, a chemical currently used by dentists to eradicate biofilm. “Our HfO2nanoparticles are far more efficient at killing the bacteria and reducing the biofilm burden both in cell cultures of bacteria and in [infected] rats,” said Ostadhossein, noting that their new technology is also much safer than conventional treatment.

Source: https://bioengineering.illinois.edu/

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