Nano-sized robots to aid root canal treatment

By NT Correspondent

Bengaluru: Researchers at the Indian Institute of Science (IISc) in Bengaluru have developed nano-sized robots that can boost the success of the root canal treatments.

The robots, according to the researchers, can kill bacteria deep inside the teeth.

Root canal treatments are routinely carried out to treat tooth infections. The procedure involves removing the infected soft tissue inside the tooth, known as the pulp, and flushing the tooth with antibiotics or chemicals to kill the bacteria that cause the infection.

However, the treatment fails to completely remove all the bacteria. Antibiotic-resistant bacteria, such as Enterococcus Faecalis, will remain hidden inside microscopic canals in the tooth called dentinal tubules.

“The dentinal tubules are very small, and bacteria reside deep in the tissue. Current techniques are not efficient enough to dig deeper and kill the bacteria,” said Shanmukh Srinivas, Research Associate at the Centre for Nano Science and Engineering (CeNSE), and cofounder of IISc-incubated startup, Theranautilus.

The researchers designed helical nanobots made of silicon dioxide coated with iron, which can be controlled using a device that generates a low intensity magnetic field.

These nanobots were then injected into extracted tooth samples and their movement was tracked using a microscope.

By tweaking the frequency of the magnetic field, the researchers were able to make the nanobots move at will and penetrate deep inside the dentinal tubules.

“We have also established that we can retrieve them … we can pull them back out of the patient’s teeth,” said Srinivas.

“Crucially, the team was able to manipulate the magnetic field to make the surface of the nanobots generate heat, which can kill the bacteria nearby. No other technology in the market can do this right now,” said Debayan Dasgupta, Research Associate at CeNSE.

Changes

Previously, scientists have used ultrasound or laser pulses to create shockwaves in the fluid used to flush out bacteria and tissue debris, in order to improve the efficiency of root canal treatment.

However, these pulses can only penetrate up to a distance of 800 micrometers, and their energy dissipates fast. The nanobots were able to penetrate much further - up to 2,000 micrometers.

Using heat to kill the bacteria also provides a safer alternative to harsh chemicals or antibiotics, the researchers said. The dental nanobots have been tested in mice models and found to be safe and effective.

The researchers are also working on developing a new kind of medical device that can easily fit inside the mouth, and allow the dentist to inject and manipulate the nanobots inside the teeth during root canal treatment.

“We are very close to deploying this technology in a clinical setting, which was considered futuristic even three years ago. It is a joy to see how a simple scientific curiosity is shaping into a medical intervention that can impact millions of people in India alone,” Ambarish Ghosh, Professor at CeNSE said.