You know the drill

In his Physiognomische Fragmente, published between 1775 and 1778, the Swiss physiognomist Johann Kaspar Lavater insisted that ‘clean, white and well-arranged teeth … [show] a sweet and polished mind and a good and honest heart’, while rotten or misaligned teeth revealed ‘either sickness or else some melange of moral imperfection’. Whatever one might think of the notion that one can read human character directly from the face, Lavater reminds us that dentistry has never been just about teeth. Possession of a functional, pain-free mouth is a practical necessity — we all must breathe and eat and talk — but it is also central to our sense of self. Pain in the head can seem unbearably close to the core of who we are, and stinking breath or black teeth carry a stigma that is both peculiarly personal and entirely public.

Lavater’s text embodies a profound paradox in our attitudes to dentistry, one that lies at the heart of my latest book, The Smile Stealers, and a new exhibition at Wellcome Collection in London.