Wisdom teeth are the third set of molars located at the back of the mouth. They look like first and second molars, but sometimes they are a little smaller.
They are often referred to as wisdom teeth because they are the last of the 32 permanent teeth and usually erupt between the ages of 17 and 25, when you are older and smarter.
As you may know, not everyone will develop four wisdom teeth. As you probably know, a lot of people pull it off. So, we're curious to know – why do humans have them?
Scientists studying teeth can tell you that the answer has a lot to do with the distant past, and a little bit with the present.
More powerful jaws
Just as you and your relatives have a lot of traits in common, humans and their extended family – primates – share traits in common. Monkeys, gorillas, and chimpanzees all have wisdom teeth.
Millions of years ago, early human ancestors had larger jaws and teeth than humans do today. For example, a species called "Australopithecus afarensis", named after a famous fossil specimen called Lucy, lived about 3 million to 4 million years ago.
Australopithecus alba's jaws and teeth are larger and thicker than your own. They have three huge molars and a thick enamel. These very early human skull fossils also show strong masticatory muscles.
Changes in diet
Scientists believe that the foods that early human ancestors ate, such as raw meat and plants, were more difficult to chew than today's foods and therefore required stronger jaws and teeth.
Researchers looked at marks and microscopic wear patterns on fossilized teeth to figure out what their extinct ancestors might have eaten.
Due to many factors, including agriculture, cooking, and food storage, food is much softer today than it was in the past. Softer, easier-to-chew foods mean less work for your teeth.
As a result, modern humans have evolved smaller jaws and flatter faces than our extinct ancestors because our food doesn't need big, sharp teeth like theirs.
Considering these changes that have slowly occurred over millions of years, the third molar, the wisdom tooth, may not be as important as it used to be.
Missing wisdom teeth
Today, about 25% of people are completely missing at least one wisdom tooth, meaning it doesn't form at all. While people don't occasionally develop other teeth, wisdom teeth are more common.
Scientists aren't sure why this is the case, but it may have something to do with the genes you inherited from your parents. Some scientists believe that the absence of wisdom teeth is an advantage for modern people with smaller jaws. A smaller jaw is certainly easier to accommodate fewer teeth.
Sometimes, due to lack of space, wisdom teeth get stuck inside the jaw and never fully erupt, or only partially erupt.
So-called impacted wisdom teeth are commonly found in the lower jaw rather than in the upper jaw. If wisdom teeth only partially erupt, people sometimes experience pain, tooth decay, or inflammation of the gums, which is why they will have the wisdom teeth removed by the dentist.
However, if the wisdom tooth is fully grown in the mouth, in the correct position, and healthy, it usually does not need to be removed.
Your dentist can examine your mouth to see if your wisdom teeth are present, or look at x-rays of your jaw** if these last molars haven't yet appeared, and you suspect they may be impacted.
If your wisdom teeth need to have any** or extractions, your dentist will also advise you. At the same time, brushing your teeth at least twice a day and flossing your teeth every day can help keep your teeth healthy.
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