Some people have problems with gums that don't conform to their teeth as well as they should. Gums should be snug around the base of teeth so the teeth can be anchored firmly and grow properly.
Conditions such as prolonged or untreated gum disease can actually cause gums to separate from teeth and form opportunistic pockets for bacteria and other debris; decay can also cause further deterioration.
Left untreated, these pockets can lead to serious infections that cause bone loss, making tooth extraction very likely.
A procedure called pocket reduction, or flap surgery, was developed to correct this problem. The procedure involves scraping away hard deposits such as tartar or calculus and reshaping damaged bone, with the eventual goal of reducing the size of the pocket and allowing the tissues to firm up around the teeth.