Wisdom teeth function and purposes

Wisdom teeth are the third and final set of molars that most people get in their late teens or early twenties. ... Wisdom teeth also can be impacted -- they are enclosed within the soft tissue and/or the jawbone or only partially break through or erupt through the gum.

Function and purpose of wisdom teeth 

Wisdom teeth are believed to be "evolutionary relics," and were helpful to our distant ancestors who ate diets that consisted of rougher foods like sticks and reed plants. As teeth wore down or fell out, wisdom teeth provided replacements. Nowadays, with modern advancements in oral hygiene and softer diets, we don’t need these replacement teeth, but they still grow in. Essentially, our mouths can hold 28 teeth, but including wisdom teeth, we have about 32 teeth all vying for space. Wisdom teeth symptoms such as overcrowding, bone and nerve damage, infection, etc. can all result.