Recurrent double lip: literature review and report of a case.

Double lip is a rare oral anomaly caused by hyperplastic tissue of the labial mucosa that becomes more prominent with tension caused by smiling. This congenital or acquired abnormality can interfere with chewing, speaking, and esthetics. Recognition of double lip and appropriate surgical treatment can reduce these potential problems. The purpose of this article is to review the literature regarding double lip and present an unusual case of recurrence simultaneously involving the upper and lower lips.