I wonder if among some humans, jaws started shrinking (as an evolutionary change? or mutation?) and the teeth didn't quite catch up, or shrink up in time. I had really crooked teeth as a kid and had to wear braces, as many children these days do. It's just wierd though, I've never seen an old skull with crowded, crooked teeth. There's probably a reason but that information has gone into hiding probably, along with a lot of other anthropological research and discoveries, as that goes against our blindly PC society.
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It’s all got to do with Vitamin K2.
One of the best blogs on this topic.
http://wholehealthsource.blogspot.com/search/label/dental%20health