I am sure you've gone through the uncomfortable process of getting your bite-wing x-rays done, later just to find out that you have new friends moving into the back of your jaw. Or, if you don't keep up with your teeth with your dentist, you developed an odd pain in your jaw. Ironically those 4 teeth are commonly named "wisdom teeth", but in proper terms the third set of molars.
Wisdom teeth are called what they are because they commonly begin to surface around "years of wisdom" anywhere from the ages of 17-25 years. It is rare, but some people never end up having their wisdom teeth come in.
So, why do we grow teeth that are most likely to be extracted in the future anyway? Evolution is the answer. We can thank our early ancestors for our pain and dental bills. During the hunter and gathering days, those teeth were needed because of their diets. Lucy definitely did not have our fancy cutlery to cut her meals with. The third set of molars came in handy when consuming rough food like meats, roots, and nuts. It required extra force and strength provided by wisdom teeth which we do not need anymore since we have proper tools to break our rough foods into small pieces. As we evolved, our jaws became smaller along with many other features. Because of this selection, the wisdom teeth now tend not to have the space it used to have before. Therefore, in the present these teeth find a comfortable way for them to grow in due to the lack of space even if it grows side ways to impact your other teeth. Ultimately, this leads to impacted teeth and overcrowding which can make this situation worse with infection, inflammation, tooth decay, and gum disease. Along with gum disease, it can lead to cardiovascular health problems since they are associated. It's always a misconception that dentist just want to remove the teeth for cosmetic reasons, and this presents to you why it is not for cosmetic reasons. Besides that overcrowded teeth is not attractive, whatever you ate that day can deeply get stuck in between your teeth and gums which can lead to infections because your brush or floss cannot reach that place.
You're probably thinking, why can't we just evolve again to get rid of this evolutionary byproduct? Evolving is not easy. It took us millions of years to be the way we are today. It would be extremely costly to use our energy to just get rid of those 4 small teeth, meaning it most likely will remain as a part of our body that became useless due to evolution.
This small pain is much better than running after your meal every day, if you can even catch your meal that day. At least we evolved to be intelligent which now makes us capable of dealing with this wisdom that brings us pain.
http://www.icr.org/article/lack-room-for-wisdom-teeth-proof-evolution/
http://www.everydayhealth.com/dental-health/why-do-we-have-wisdom-teeth.aspx
