Facial asymmetry: etiology, evaluation, and management.

Facial asymmetry is common in humans. Significant facial asymmetry causes both functional as well as esthetic problems. When patients complain of facial asymmetry, the underlying cause should be investigated. The etiology includes congenital disorders, acquired diseases, and traumatic and developmental deformities. The causes of many cases of developmental facial asymmetry are indistinct. Assessment of facial asymmetry consists of a patient history, physical examination, and medical imaging. Medical imaging is helpful for objective diagnosis and measurement of the asymmetry, as well as for treatment planning. Components of soft tissue, dental and skeletal differences contributing to facial asymmetry are evaluated. Frequently dental malocclusion, canting of the occlusal level and midline shift are found. Management of facial asymmetry first aims at correcting the underlying disorder. Orthognathic surgery is performed for the treatment of facial asymmetry combined with dental occlusal problems. A symmetrical facial midline, harmonious facial profile and dental occlusion are obtained from treatment. Additional surgical procedures may be required to increase or reduce the volume of skeletal and soft tissue components on both sides to achieve better symmetry.