Mounting evidence suggests that the microbes in our mouths could be putting us at risk of certain cancers, as well as affecting our prognosis if we do develop them, but the relationship isn’t straightforward.

Second only to the gut, the mouth is home to a diverse microbial community, with more than 700 species of bacteria alone colonising our teeth, tongues and soft tissues.

Over the past decade, research has increasingly linked gum disease…