B1 中級 美國腔 3111 分類 收藏
Each year, five million Americans
get their wisdom teeth removed,
which costs about three billion dollars in total medical costs.
But for many, it's worth it,
since leaving them in can cause serious problems
like gum infection, tooth decay, and even tumors.
But wisdom teeth
weren't always the unwelcome threat we see today.
Wisdom teeth have been around for millennia.
Our ancient ancestors
used them the same way we use our other eight molars:
to grind up food,
which was especially handy before the advent of cooking
around seven thousand years ago,
back when our diet consisted of raw meat
and plants that were fibrous and tough to chew.
But once we got our hands on softer cooked foods,
our powerful jaws no longer needed to work as hard
and shrank as a result.
But here's the problem:
The genes that determine the size of our jaws
are completely separate from the genes that determine
how many teeth we grow.
So as our jaws shrank,
we still kept all 32 teeth.
And it eventually got to the point
where there wasn't enough space to fit all of the teeth.
But why did wisdom teeth specifically get the boot?
Well, they're the last to show up to the party.
Wisdom teeth don't usually grow in until you're between
16 and 18 years old.
And by that time, chances are your other 28 teeth
have taken up all the available space in your mouth.
In that case,
instead of growing in like a normal tooth
wisdom teeth get trapped or impacted in your jaw,
which often makes them grow in at odd angles
and press against your back molars
causing pain and swelling.
It also forms a narrow crevice between the teeth
creating the perfect food trap.
This makes the tooth difficult to clean
which attracts more bacteria
and can cause infection and tooth decay,
eventually leading to gum disease if left untreated.
But it gets worse.
Tooth decay can eventually destroy your wisdom tooth.
So, to save you and your teeth
from such a horrible fate,
dentists will often remove wisdom teeth
before they go rogue.
Seems reasonable, right?
Well, it's actually a controversial topic
among some in the dental community.
The worry is that we're removing
our wisdom teeth too frequently,
often when it's unnecessary
and the teeth pose no threat,
like if your mouth is big enough
or you're one of the 38 percent of people
who don't develop all four wisdom teeth.
In that case, risks from surgery
like infection and nerve damage
pose more danger than the teeth themselves.
But the fact remains.
When wisdom teeth do become a problem,
you'll curse the day we invented cooking.


為什麼智齒這麼討厭? (Why Do Wisdom Teeth Suck?)

3111 分類 收藏
Evangeline 發佈於 2018 年 11 月 4 日    Amber Li 翻譯    Evangeline 審核
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