It's pretty clear that all of Jada's teeth are "shark teeth," meaning that instead of growing right under/over her baby teeth, her adult teeth poke out behind them. Besides lending her grin a certain charm, this has the effect of making it take much longer for her to lose her teeth, since her baby teeth's roots aren't being worn away by her adult teeth.
Her first two lost teeth were actually pulled by the dentist, and her first real lost tooth was literally lost, in her friend's backyard. But Amy has pulled the last two, including last night. She has three other visible shark teeth, so hopefully those will go soon too. I like her smile, but having her baby teeth stick out of her mouth at 45 degree angle just looks weird (plus it makes her take hours just to eat one piece of fruit, it seems).