I think Anna Paquin has a lot to do with this. On this "cycle" of America's Next Top Model, there's a contestant who looks so much like her, gap and all. On last night's episode, Tyra sent her to the dentist to have her gap widened by having 1/4 mm shaved off of each front tooth.

Also, check out this documentary from 1987:

http://www.imdb.com/title/tt0095199/