An army of tiny robots scuttling about inside your mouth cleaning your teeth. It's a disquieting thought, and yet it might be one of the most effective ways to deal with the sticky bacterial biofilms that coat our choppers – as well as water pipes, catheters and other tough-to-clean items.
Run your tongue around your teeth and enjoy the feeling of the biofilms that are pretty much always coating them. Biofilms are little communities of micro-organisms, bacterial and otherwise, that gather together, sticking their cell walls together and bonding themselves to surfaces in three-dimensional structures, scaffolded together with all sorts of claggy polymers. They've been described as little microbe cities, functioning as tiny co-ordinated communities.
They form all over the place – not just in our mouths as dental plaque, but on your dirty dishes, on rocks, in pipes, surgical equipment, anywhere liquid and microbes meet – and when bacteria gang up in these gloopy films, they can become far more resistant to antibiotics than usual.
And they're tough to break – hence why dentists have to spend so much time scraping away at plaque deposits on your teeth in a fiddly and uncomfortable process that's probably about as much fun for the dentist as it is for the patient.