A Frenum is a naturally occurring muscle attachment, normally seen between the front teeth (either upper or lower). A lack of attached gingiva, in conjunction with a high frenum attachment can result in recession. An excessively large frenum can prevent teeth from coming together resulting in a gap between front teeth. In either case the frenum need to be released from the gum with a frenectomy.
When Orthodontic treatment is planned, the removal of an abnormal frenum, with or without a gingival graft, can increase stability and improve success of the final orthodontic result.