When I was younger, I remember my wisdom teeth giving me a bit of grief when they started to emerge.
Eventually the pain went away by itself, but for others it’s not that straight-forward.
Wisdom teeth can be a real pain — not just in the mouth, but for the hip pocket.
But why do we have these teeth anyway, and is it always best to have them out?
Why do we have wisdom teeth?
Wisdom teeth are our third and last set of molars, which are the big chewing teeth right at the back of your mouth.
They get their name because they typically emerge when you become an adult, and — apparently — get “wisdom”.
But it turns out we don’t actually use these teeth much at all. So why do we have them?
Well, there was a time when wisdom teeth were important to the survival of the human species.
“They’re part of our evolutionary heritage,” says Tanya Smith, an expert in the evolution of teeth from Griffith University.
When we were hunters and gatherers, feeding ourselves was tough work.
What we collected needed a lot of grinding work before it could be swallowed.
So early species in the human family had bigger mouths, bigger and more complex teeth — and actually used their wisdom teeth to chew, Professor Smith says.
But over the aeons our diet changed, especially after the invention of agriculture.
“It included softer, less mechanically demanding food, and so there wasn’t the same pressure to maintain large jaws and faces,” Professor Smith says.
Add to this today’s ultra-processed microwaved diets, and wisdom teeth have become nothing but a pretty useless evolutionary relic.
Why do wisdom teeth cause problems?
Today, our jaws are much smaller than our ancestors’, so many of us don’t have enough space in our mouth for wisdom teeth to emerge easily, or else other teeth get in the way.
So sometimes wisdom teeth become “impacted” — either partially or fully trapped in your gums or jawbone.
Most people won’t get problems from impacted wisdom teeth, but in some cases they can lead to inflammation, infection, or dental decay in the adjacent teeth.
And the result can be very painful.
Despite popular belief, though, there is no evidence that impacted wisdom teeth push other teeth out of alignment.
On average 25 per cent people around the world have impacted wisdom teeth, Professor Smith says.
But some ethnicities have a higher rate of impaction, with the figure in European populations being over 70 per cent.
How many wisdom teeth should you have?
Some people are lucky enough to lack wisdom teeth altogether, while others may only develop one one, two or three. All of these scenarios are known as “third molar agenesis”.
Again, it varies a lot with ethnicity.
A global review of research on third molar agenesis found the worldwide rate was 22.63 per cent.
The rate in Europeans was close to this average at just above 20 per cent; people in Africa had the lowest level of agenesis at about 5 per cent, and Asians the highest around 30 per cent.
Interestingly, what determines the number is not just genetics. Even identical twins can have different numbers of wisdom teeth.
Should you have your wisdom teeth out?
Experts recommend removing wisdom teeth if they are causing problems.
But what about removing non-problematic wisdom teeth, just in case?
In 2016, a review by the Cochrane Collaboration found insufficient evidence to support removal of disease-free wisdom teeth, but noted the poor quality of evidence available.
In 2020, the National Institute for Health and Care Excellence in the UK also found there was “no reliable research” that prophylactic removal of impacted wisdom teeth helped people.
On the other hand, it said, the risk of wisdom teeth removal can lead to nerve damage, damage to other teeth, infection, bleeding and — rarely — death.
