The muscles of the cheek and lip are attached to the gum tissue of the mouth by a piece of soft tissue called a frenum. Sometimes a frenum can be attached on the gum tissue too close to the teeth causing tissue recession, or actually between the teeth which can contribute to the spaces between teeth.
After orthodontic treatment closes the spaces between the front teeth, a abnormal frenum attachment can push the teeth back apart.
A Frenectomy is a simple surgical procedure in which either part, or all of the frenum is removed. The frenum is then allowed to heal in an area farther away from the teeth.