Nano-sized robots manipulated with a magnetic field can help kill bacteria deep inside teeth to ensure the success of root canal treatments after living tissue has been removed, scientists report.
Root canals are routinely performed to treat dental infections in millions of patients.
The procedure involves removing the infected soft tissue inside the tooth, called the pulp, and rinsing the tooth with antibiotics or chemicals to kill the bacteria causing the infection.
But often the treatment does not succeed in completely removing all bacteria – especially antibiotic-resistant bacteria such as e.g Enterococcus faecalis – which remain hidden in microscopic canals in the tooth called dentinal tubules.
Now scientists from the Indian Institute of Science (IISc) and the IISc-founded startup Theranautilus say they are close to clinical trials of the new technology, which will use nanorobots to clean dentin tubules.
Shanmukh Srinivas, Research Associate at the Center for Nano Science and Engineering (CeNSE), IISc, and co-founder of Theranautilus, said: “The dentinal tubules are very small and bacteria reside deep in the tissue. Current techniques are not efficient enough to go all the way in and kill the bacteria.”
In the study, published in Advanced Healthcare Materials, the researchers designed spiral nanobots made of iron-coated silicon dioxide that can be controlled with a device that generates a low-intensity magnetic field. These nanobots were then injected into extracted tooth samples and their movement tracked with a microscope.
By adjusting the frequency of the magnetic field, the researchers were able to get the nanobots to move at will and penetrate deep into the dentinal tubules. “We also found that we can retrieve them…we can pull them out of the patient’s teeth,” says Srinivas.
Crucially, the team was able to manipulate the magnetic field to cause the nanobots’ surface to generate heat that can kill nearby bacteria. “No other technology on the market can do that right now,” says Debayan Dasgupta, research associate at CeNSE and another co-founder of Theranautilus.
Historically, scientists have used ultrasonic or laser pulses to create shock waves in the fluid used to flush out bacteria and tissue debris to improve root canal treatment efficiency. However, these pulses can only penetrate to a distance of 800 microns, and their energy dissipates quickly. The nanobots could penetrate much further – up to 2,000 micrometers. Using heat to kill the bacteria also offers a safer alternative to harsh chemicals or antibiotics, the researchers say.
Theranautilus grew out of several years of work on magnetically controlled nanoparticles carried out in the laboratory of Ambarish Ghosh, a professor at CeNSE. His group, along with collaborators, have previously shown that such nanoparticles can capture and move objects with light, swim through blood and inside living cells, and adhere strongly to cancer cells.
“These studies have shown that they can be used safely in biological tissues,” says Dasgupta.
The team tested the dental nanobots in mouse models and found them to be safe and effective. They are also working on developing a new type of medical device that fits easily in the mouth and allows the dentist to inject and manipulate the nanobots into the teeth during root canal treatment.
“We are on the verge of using this technology in a clinical setting that was considered futuristic three years ago,” says Ghosh. “It is a joy to see how a simple scientific curiosity translates into a medical intervention that can affect millions of people in India alone.”
This story was provided to Newsweek by Zenger News.
https://www.newsweek.com/tiny-bots-could-deep-clean-teeth-say-experts-1708384 Tiny bots could thoroughly clean teeth, experts say