Here's a Child's Skull, Showing Their Baby Teeth With The Adult Teeth Above them!

  • ClimateChangeAnxiety [he/him, they/them]
    ·
    3 years ago

    I never thought about the teeth maintaining the shape of the jaw! In retrospect that makes a lot of sense, cause if your teeth are crooked enough they have to break and reform your jaw don’t they? Although this prompts another question

    Another reason why we have two sets of teeth is that our teeth can’t actually grow. Once they are fully developed, they stay the same size and can not grow bigger or longer like our nails or hair

    Why is this? What’s so fundamentally different about our teeth that they can’t grow and change over time, when other hard parts of our bodies like bones, nails, and hair can?

    • emizeko [they/them]
      ·
      edit-2
      3 years ago

      tooth enamel is the hardest part of the body, probably why it can't grow (I don't think enamel has any living cells in it), and under that they're made of dentin not keratin (or whatever bone is) which is less hard but still harder/denser than keratin and bone

      that was from the top of my head but wikipedia confirms:

      Enamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%), with water and organic material composing the rest. The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. Enamel is formed on the tooth while the tooth develops within the jaw bone before it erupts into the mouth. Once fully formed, enamel does not contain blood vessels or nerves, and is not made of cells. Remineralisation of teeth can repair damage to the tooth to a certain degree but damage beyond that cannot be repaired by the body.

      • ClimateChangeAnxiety [he/him, they/them]
        ·
        edit-2
        3 years ago

        Ah yes, and interestingly while bones are living tissue mostly made out of cells, teeth aren’t. They’re basically just small fancy rocks attached to our mouths. The fact that they aren’t made of cells is crazy to me

        • SoyViking [he/him]
          ·
          3 years ago

          Small fancy rocks that will bankrupt you if anything goes wrong with them.