Five teeth total so far.

It could be a coincidence, but after the fireworks update it took me 4 hours to gain one tooth. Much longer than before. Its about 7k XP per tooth. LOL. I think I'll just save whatever teeth I get for whatever comes in the future. Def not worth wasting teeth on that legendary gear. My damage would go down with that gear. Should be better than that for the level of grinding required.