National Tooth Fairy Day is always celebrated on February 28 or on August 22. Documentation on websites is fairly evenly divided, with slightly more recording it on February 28th. Some very reputable and authoritative sites differ on the date. Until further documentation is found, feel free to celebrate it on either date, or you can celebrate it on both.
The small fairy responsible for collecting baby teeth is traditionally depicted as female. In Medieval Europe baby teeth were buried in hopes of growing permanent teeth, according to the University of Florida's Center for Children's Literature and Culture. In the U.S. when a child looses baby teeth, they are instructed to place them under a pillow. In the morning the tooth has been magically replaced with money.
On this day, you can encourage kids to brush and floss, read the child a book about the tooth fairy and replace worn toothbrushes with a new ones.