Fine, chair of the school's Department of Oral Biology, said further studies are needed to test real-life efficacy in humans.
That doesn't translate directly to effectiveness in prevention, and many people don't understand that.
The TIDREC research has been accepted by the British Dental Journal BDJ and was published as a Letter on 26 June 2020.
One potential downside: Frequent use could change the microbiome in the mouth and nose, which includes the good germs, Hoffman points out.