Add Yahoo as a preferred source to see more of our stories on Google. A stained section of a tooth organoid grown in the lab at King’s College London. - Dr. Xuechen Zhang It’s not surprising that many ...

For decades, small grooves on ancient human teeth were thought to be evidence of deliberate tool use—people cleaning their teeth with sticks or fibers, or easing gum pain with makeshift "toothpicks." ...

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How did two sets become standard for human beings?