Principles of soft tissue augmentation for the aging face.

In the quest for the "ideal" soft tissue filler, many diverse products have been developed. The expanding market of available fillers is a testament that no one product will ideally suit all patients or clinicians. In addition, the challenge of satisfying the criteria of an ideal filler has driven researchers to take a variety of development paths. This has resulted in multiple categories to characterize soft tissue fillers. These fillers are categorized according to: (1) filler material, eg, autologous, natural, synthetic; (2) mechanism of action, eg, void filler, neocollagenesis, fibroblast stimulation; (3) patient type and profile, eg, younger versus older patient, rhytids versus "sinking and sagging" skin; or (4) durability of treatment effects, eg, temporary, semi-permanent, or permanent. Although strategies for soft tissue augmentation may be quite diverse, strategies should share a universal goal to address fat redistribution (atrophy and hypertrophy), the primary underlying morphological cause of facial aging. To accomplish this, volumizers are now available that are injected more deeply, resulting in the restoration of supportive structure and foundation. These can be used in combination with other products that are used more superficially for smoothing skin surfaces. As numerous soft tissue fillers enter the market, mechanisms and injection techniques become more divergent, and therefore require that the dermatologist and cosmetic surgeon receive adequate training to use products safely and effectively. This manuscript provides an overview of soft tissue fillers and their proper use.