A frenum, also known as a frenulum, is fibrous band of tissue that prevents movement.  In the mouth, these frenum should be well below the gingival margin.  In some cases, an aberrant frenum can be positioned near the neck of the tooth and cause movement of the gumline, increase plaque accumulation, and prevent orthodontic closure.

A frenectomy, or the removal of the frenum attachment, is a quick and easy procedure performed in the dental office under local anesthesia.