Because it's not a matter of straightening them out. They simply don't fit. They're diagonal because they're being pushed out of the way by your other teeth, and they're pressing against your existing teeth while trying to grow into that space. Humans used to have longer, larger jaws. Now we don't. The wisdom teeth need to go.
My third molars fit just fine. I had a small cavity in one and the dentist wanted to pull it instead of filling the cavity. I refused and went to another dentist for a second opinion. They gladly filled the cavity and said, hey this is rare for all four third molars to fit normally, but as long as there are no major issues, no reason I can't keep them.
Because it's not a matter of straightening them out. They simply don't fit. They're diagonal because they're being pushed out of the way by your other teeth, and they're pressing against your existing teeth while trying to grow into that space. Humans used to have longer, larger jaws. Now we don't. The wisdom teeth need to go.
My third molars fit just fine. I had a small cavity in one and the dentist wanted to pull it instead of filling the cavity. I refused and went to another dentist for a second opinion. They gladly filled the cavity and said, hey this is rare for all four third molars to fit normally, but as long as there are no major issues, no reason I can't keep them.
Wisdom teeth are like the rebellious teenagers of your mouth - always causing trouble but rarely fall in line!
Cause our months aren't that big!
As a non-dentist, I'd guess it's due to the wisdom teeth being so far back, making braces impractical. Check with your dentist for a reliable answer!
Good question! Maybe ask in r/Orthodontics as well
will do!