Clinical validation of the upper face first principle-A clinical, prospective, interventional split-face study.

Background: Previous clinical and anatomic investigations have identified the clinical relevance of facial biomechanics. Based on this new understanding, principles for facial aesthetic procedures were established: Lateral Face First, Deep Layers First, and Upper Face First.

Objective: To test the upper face first principle by showing that an injection sequence, starting in the upper face is superior to an injection sequence starting in the lower face.