The nanocomposite is made up of silver nanoparticles and calcium phosphate nanoparticles, both of which are piped into the tooth as filler for a cavity. The silver nanoparticles along with a few other ingredients in the material kill off whatever bacteria is still lingering inside the tooth, paving the way for the calcium phosphate to regenerate tooth minerals. Over time, the tooth strengthens again.
But as IEEE Spectrum notes, the silver nanoparticles could prove to be problematic, and this is probably why this treatment is offered as a cavity filling rather than a toothpaste or mouthwash. Silver nanoparticles aren’t totally understood, and there have been some concerns voiced about the potential risks and perils associated with ingesting the stuff. The nanocomposite is currently undergoing both human and animal testing right now, hopefully with an eye toward clarifying and alleviating any health concerns. If the composite can pass muster, dentists everywhere can get down to the business of rolling back the clock on cavities.