I trust dental hygienists to perform intimate acts on me, even though or maybe because, I would not be able to recognize them on the street. Their fingers are always in my mouth so I can’t ask them to ask them what they have learned about people from cleaning their teeth. Like can you tell if a person is left or right handed by their teeth? Can you tell if they were vegetarian? Can you be a kind of Sherlock Holmes by looking at the mouths of people, to understand their hidden habits? Does flossing relate to other personal characteristics?