An 18th century hand-illustrated page from an Ottoman Turkish dental book showing a molar infected with tooth worms. As early as Babylonian times and lasting well into the 18th century, it was thought that a toothache was caused by worms. (The theory was disproved by Jacob Christian Schaffer in 1757.) In a cavity on one side of the bisected tooth, Lucifer watches as two worms devour and entrap their victims. In the other half of the tooth, demons lord over a collection of human skulls.