How does the Tooth Fairy get into the house and then your room you ask? If you have not figured it out already the Tooth Fairy is magical. I make a potion of special Tooth Fairy dust that I sprinkle on my wings which allows me to squeeze through cracks, slide down vents and if need be walk through thin glass, although that is not my preferred method.
Once I have received the tooth put the money under a pillow, I need to sprinkle the dust on the new tooth so that it can shrink and I put it my bag with all of the other teeth that I have collected.
If you look very carefully, after a visit from the Tooth Fairy you may find left over dust in your room.