The situation of receding gums happens when the tissue of the gum around the teeth corrodes and it looks like your gums recede backwards. Then a large surface of the teeth is exposed and more visible.
When the gums go back, the space between the gum line and the teeth rises. That is perfect place for bacteria growth. Another problem that may happen is over exposure of the root of the tooth that can lead to extreme pain and sensitivity of the tooth. It will also have a negative influence over the structure and bone of the tooth that can cause losing of the tooth.
This is a very common problem and most of the people who suffer from it do not notice the problem. The reason is because the process is slow and happens gradually. Remember to check your gums if you teeth have become very sensitive. That is one of the first signs.