What does it mean when you dream of a person who has died and that dead person gives you a tin container of baby teeth?

Dreams communicate through symbols. This dream seems to refer to the dreamer's past. The identity of the deceased is important for understanding the dream; a dead parent would be a different metaphor than a dead sibling or a dead spouse. The container of baby teeth refers to something that the dreamer has lost, and did not consider important when it was lost.