3. The complex smile characterizes 2% of the population.The shape of the lips are typically illustrated as two parallel chevrons. The levators of the upper lip, the levators of the corners of the mouth, and the depressors of the lower lip contract simultaneously, showing all the upper and lower teeth concurrently. The key characteristic of this smile is the strong muscular pull and retraction of the lower lip downward and back. In this smile pattern both maxillary and mandibular incisal planes are generally flat and parallel. Some celebrated personalities with complex smiles include Julia Roberts, Marilyn Monroe, Will Smith and Oprah Winfrey.