Wisdom teeth- Last in, first out (sometimes)
Wisdom teeth, or third molars, are the last permanent teeth to take their place in your mouth, sometime during your late teens or early 20s.
If they come in properly, wisdom teeth can be an asset, but many times, there isn't room for wisdom teeth in the jaw. When this happens, the teeth become impacted- they can't fully emerge from the gum tissue. Impacted teeth can damage adjacent teeth. Partially erupted wisdom teeth are difficult to clean and provide an opening for bacteria to settle beneath the gum line, where they can cause an infection.