The Indian Institute of Science (IISc) in Bengaluru has developed nano-sized robots (nanobots) that can kill bacteria deep inside human teeth.
The IISc researchers said that these nanobots can be controlled through their magnetic fields.
The new nanobots could boost the success of root canal treatments.
How the nanobots work
Root canal treatment is a standard procedure used by dentists worldwide to treat tooth infections.
However, the IISc researchers say that the treatment fails to completely remove all the bacteria in the infected tooth.
They say that antibiotic-resistant bacteria such as Enterococcus faecalis remain hidden inside microscopic canals — called dentinal tubules — in the tooth.
“The dentinal tubules are very small, and bacteria reside deep in the tissue. Current techniques are not efficient enough to go all the way inside and kill the bacteria,” explained Shanmukh Srinivas, research associate at the Centre for Nano Science and Engineering (CeNSE) at IISc.
A study published in Advanced Healthcare Materials reveals that the researchers designed helical nanobots made of silicon dioxide.
Tracking the nanobots
The bots are coated with iron and can be controlled using a device that generates a low-intensity magnetic field.
The study shows that the nanobots’ movement into extracted tooth samples could be tracked using a microscope.
By tweaking the magnetic field frequency, the researchers could 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 from the patient’s tooth,” said Srinivas.
In a crucial development, the team succeeded in manipulating nanobots’ surface so that it generates heat to kill the bacteria nearby.
Previously, scientists used ultrasound and laser pulses to create shockwaves in the fluid to flush out bacteria and tissue debris to improve the efficiency of root canal treatment.
But these pulses penetrate only up to 800 micrometres, and their energy dissipates fast. The nanobots, on the other hand, penetrate much deeper — up to 2,000 micrometres.
Researchers say that using heat to kill the bacteria also provides a safer alternative to harsh chemicals or antibiotics.
Study on mice
The researchers tested the dental nanobots in mice models and found them safe and effective.
They are now working on developing a new medical device that can easily fit inside a human mouth to allow the dentist to inject and manipulate the nanobots inside the teeth during a root canal treatment.
According to the IISc researchers, they are very close to deploying this technology in a clinical setting.