People of ancient times believed that the stabbing pain of a toothache was caused by a toothworm, which either had appeared spontaneously or had bored its way into the tooth. If the tooth pain was severe, it meant that the worm was thrashing about; but if the aching stopped, then the worm was resting. Cultures all over the world, many of whom had no contact with each other, held stubbornly to this myth. The folklore of the toothworm persisted from ancient times to the beginning of the eighteenth century.