The next time you visit your dentist, show a little appreciation for the techniques that keep your teeth clean and white. There was a time when grinning was considered a sign of dementia.

If you showed a toothy grin in the 18th century, you would have been considered loony, partly because most people’s teeth were in terrible shape. In polite society in those days people were tight-lipped and baring one’s teeth was considered rude and low class.

It was an artist who actually shocked society at the time with a self-portrait of an open-mouth smile showing, of all things, a glimpse of teeth. While the portrait by court artist Louise-Elisabeth Vigee-Lebrun was frowned upon, many notables soon began to have their portraits painted with their teeth on show.

The artist’s portrait coincided with advances in French dentistry, which was greatly needed since teeth quality had deteriorated from drinking tea, coffee and eating chocolate. A lot of money was invested in early forms of dental care because of the demand from consumers, particularly in higher society.

The result was the invention of aesthetically-pleasing procelain teeth to replace wooden ones and the invention of spring-loaded dentures. Other products were developed to keep the mouth and teeth cleaner and fresher.