This is a common surgical procedure that removes gum tissue, bone or both to expose more of a tooth. Sometimes, not enough of the tooth sticks out above the gum to support a filling or crown. This can be needed because of a broken tooth, or when a crown or filling falls out and there is decay underneath.
The gums will be cut and pulled away from the tooth to expose the roots and bone. Gums and often bone need to be removed in order for there to be enough space for adding crowns or fillings.