What is double lip line?

Double lip is a rare congenital anomaly which occurs due to incomplete vertical fusion of the maxillary and mandibular processes during embryonic development. It is characterized by a fold of excess tissue on the upper or lower lip that creates a double ridge appearance. Double lip can be classified into two types: complete and incomplete. Complete double lip encompasses the entire lip and may cause functional and aesthetic issues. Incomplete double lip only involves a specific segment of the lip and generally presents no functional issues. Double lip can be corrected through surgery, which involves removing the excess tissue.