Earlier this year, I was teased by news that graphene could be ‘tattooed’ to one’s tooth to detect harmful bacteria. I say teased because the bacteria that could be detected was not the Streptococcus mutans bacteria that causes tooth decay. Instead the device could detect just about every other bacteria except that one. So, what appeared to be a story that might be able to redeem me in the eyes of the dental community—after I echoed others’ doubts about the efficacy of a nanofilm in promoting cell growth in decayed teeth—just wasn’t the opportunity I had hoped for.
This week, however, researchers at the University of Maryland have offered up a technology that should be of keen interest to the dentists of the world, and those who visit them. The researchers have developed a nanocomposite that can be used not only as a filling for the cavity, but also can kill any remaining bacteria in the tooth and regenerate that tooth’s structure that had been lost due to the decay. You can access a PDF file that offers up a poster presentation of the research here.
The basis of the nanocomposite are calcium phosphate nanoparticles that regenerate tooth minerals. The ingredient that kills off the remaining bacteria in the tooth is made up of silver nanoparticles and quaternary ammonium along with a high pH. According to the news release, the alkaline pH is the feature that limits the acid production by the bacteria. This begs the question: why not just develop a mouthwash with these ingredients so you don’t need the cavity filling in the first place?
One answer may be the use of silver nanoparticles, which are not without some controversy when associated with anything that might be consumed by humans. Sure enough, just a quick perusal to see how this story was being covered turned up a blog called “Beyond Pesticides” that offered up this headline: “New Dental Fillings Utilize Controversial Nanotechnology to Kill Bacteria”. The blog goes into some detail about the potential risks of silver nanoparticles.
The researchers are continuing with their animal and human testing with the nanocomposite. Given that some sectors of the public are concerned about the potential risks of silver nanoparticles, they should probably take a look at the issue as part of their research.
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.