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Wisdom Teeth & Evolution – Why You Have Them if You Don’t Need Them

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Doring Kindersley/Getty Images

Evolution has done a pretty bang up job when it comes to making our bodies fit for modern life. We’ve kept the things that help protect us against the daily onslaught of bacteria, like eyelashes and those little nose hairs. And we’ve phased out what we no longer need, like a thick pelt all over our bodies.

But there are still some vestiges of our long ago ancestors that we don’t really need anymore, like wisdom teeth. Kind of a funny name for something most people end up getting rid of, right?

So what gives? Why hasn’t our smart biology phased them out yet? And why do some people have to have theirs removed while others can let them stay? Read on to get the lowdown.

What Are Wisdom Teeth?

The third molar or wisdom tooth is right at the far end of your row of teeth. They often appear between the ages of 17 and 25. They’re known as “wisdom teeth” for precisely this reason – theyusually grow in well after the time your other adult teeth come in, so they’re a sign of physical maturity, or “wisdom” as it were.

History of the Wisdom Tooth

Let’s take a look back at our ancestors and focus particularly on their diet. Scientists have suggested that the four third molars helped our early ancestors grind down plant-based foods that were abundant in their diets at the time.

Now plant cell walls are made of something known as cellulose, which our ancestors’ digestive systems weren’t very efficient at breaking down. This plant tissue was worn down with the help of a larger jaw that had more teeth than we now do. Archeologists have discovered human skulls that are much larger than the current average skull size. And what did these larger skulls and jaws accommodate easily? More teeth of course.

Evolutionary Changes

Over many centuries, human behavior and dietary habits have gradually changed. To adapt to the new forms of diet and the improved digestive systems our, jaws have become a lot smaller. Wisdom teeth however have not disappeared entirely and still occur in most people and these extra teeth are what dentists call supernumerary teeth. However, most people don’t end up growing all 4 of them..

The presence or absence of these teeth tends to vary depending on the race of the individual. Tasmanian Aborigines, for example, have a 0% agenesis of the teeth while indigenous Mexicans have 100% agenesis. This means that the aborigines are almost entirely likely to develop the teeth while the indigenous Mexicans are equally unlikely to have them. The gene responsible for the development or lack of development of these teeth is known as PAX9.

Wisdom Teeth Removal

Due to the lack of space in the jaws of most modern people and the fact that they come in so late,they can cause problems. A growing wisdom tooth can sometimes affect the teeth around it while developing or grow out entirely sideways. Both these conditions cause immense pain. And because there’s usually not room for it, it can crowd the other teeth, causing them to be crooked. This is especially worrying to those who’ve invested time and money in orthodontics.

Wisdom teeth are also prone to cavities or periodontal disease. The risk of developing these conditions increases with age. Only 2% of people above the age of 65 are known to be living with the teeth without any complications.

If the tissue above the tooth has been affected due to the growth of this tooth the treatment is focused on the affected tissue. When the wisdom teeth are impacted or have come in sideways they are generally removed. It’s a common procedure and is usually done if there’s any concern that they could cause problems for the other teeth.

The reason most people have their third molars removed is due to dental complications such as cavities or pain. Often these teeth do not fully develop and food tends to get stuck in the spaces between the gums and tooth. The buildup of plaque can cause cavities at a later stage and also lead to immense amounts of pain. Removing a wisdom tooth in such a scenario is usually the best solution.

Wisdom teeth are not nearly as useful for us as they were for our ancestors. They usually have no room to develop and can sometimes lead to dental complications. In hundreds or thousands of years, evolution may start to phase them out even more, so that removal is no longer necessary.

But for now, it’s best to keep an eye on yours and your teenage children’s wisdom teeth so that your dentist can address any potential issues that their appearance may cause.

Image credit: Doring Kindersley/Getty Images

 

Dr. Kenneth MakAbout the Author: Dr. Kenneth Mak, co-founder of Los Angeles dental practice MKD Dentistry, is committed to educating patients and readers on the inner workings of their pearly whites. Along with Dr. Rodney Kleiger and Dr. Dennis De Mesa, Dr. Mak provides both excellent patient care and preventative education that can help people avoid serious dental problems.

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