BACKGROUND:
Facial aging is a dynamic process involving the aging of soft tissue and bony structures. The skin undergoes atrophy with a loss of tone and elasticity. Subcutaneous fat atrophies with a decreased adherence to underlying layers leading to gravitational descent. The aging process also affects the facial bones. In this study, we will evaluate how specific bony aspects of the facial skeleton change with age.

METHODS:
Facial bone computed tomography (CT) scans were obtained from 120 Caucasian subjects, (60 female, 60 male). There were twenty male and twenty female subjects in each of three age categories (20-40, 41-64, and 65+). Each CT scan underwent 3-D reconstruction with volume rendering. Edentulous patients were excluded from this study. The following measurements were then obtained from each scan: upper face (orbital aperture area, orbital aperture width and the height to the superior orbital rim and inferior orbital rim was then taken at nine equal increments allowing curvilinear analysis), midface (glabellar angle, pyriform angle, maxillary angle and pyriform aperture area), and lower face (bigonial width, ramus breadth, ramus height, mandibular body height, mandibular body length and mandibular angle). The data was then analyzed with one-way Anova, and results were considered significant at a p-value less than .05.
RESULTS:
The orbital aperture width and orbital aperture area increased significantly with increasing age for both genders. There was a significant increase in height of the superio-medial and inferio-lateral orbital rim in both genders.
The glabellar and maxillary angle decreased with age for both genders while the pyriform angle did not show significant change. There was a significant increase in pyriform aperture area for both genders with age. There was no significant change in regards to bigonial width or ramus breadth across ages for either gender. Mandibular length and height both significantly decreased for each gender. The mandibular angle increased with age, which resulted in blunting or the loss of definition of the lower border of the face.
CONCLUSIONS:These results suggest that the bony elements of the face change dramatically with age and coupled with soft tissue changes lead to the appearance of the aged face. This loss of bony volume and projection may contribute to lateral orbital hooding, crow's feet, nasolabial fold prominence, decreased mandible projection, and loss of jawline definition. We feel that with a better understanding of facial aging the most effective approach towards facial rejuvenation will be two-fold: augmentation to compensate for lost volume, and lifting and reducing the aged and less elastic soft tissue envelope. An approach for timing of such volume augmentation and patient examples will be presented for each part of the face. Example images for the lower third of the face are included below.