Yeah, 1 & 3 make sense. But genetics causing all teeth to be removed by 20? Never heard of anything like that. Is that really a thing?!? Holy freakin jesus! So this genetics thing and losing all your teeth is real!!?? How have I never heard of this. Is this due to making it harder to brush in certain places leading to decay and holes? Or is there just nothing you can do to prevent it? I always assumed that if you brushed well and regularly/consistently (enough to make sure your teeth did not erode, indicated by never needing fillings) that you were pretty safe.