Karíus og Baktus (1970)

The little tooth trolls Karius and Bactus live inside cavities in the teeth of a boy named Jens. They have a very good life, especially when Jens eats white bread with syrup and fails to brush his teeth afterwards. Eventually their homes are destroyed by the work of a dentist and they are rinsed out of Jens' mouth through proper dental care.