INTRODUCTION
With the appreciation of facial aging mechanisms and increased patient demand for minimally invasive procedures, soft tissue dermal fillers have become a cornerstone for facial rejuvenation. Fillers are implants that are injected into the various layers of the skin and subcutaneous planes and lead to immediate volumization and aesthetic improvements with minimal recovery times.1 Compared to many other forms of aesthetic intervention, dermal fillers (DFs) are temporary, less costly, ambulatory, and integrate well into the dermal matrix resulting in an improved appearance. DFs are either biodegradable or non-biodegradable. The former are gradually absorbed by the body and can last from 3-24 months while the latter are synthetic or artificial and can last nearly 5 years.2,3 The primary indications of DFs are to restore lost volume and to correct rhytids.
All currently available HA products in the United States are biodegradable fillers. Other biodegradable fillers include poly-L-lactic acid (PLLA, Sculptra Dermik Laboratories 2004, Fort Worth TX), and calcium hydroxyapatite (Radiesse Merz Aesthetics 2006, Franksville WI).4 HA was first utilized in dermal fillers in 1989 by Balazs and Denlinger and were derived from rooster crests.5 Until the addition of crosslinking agents with the first generation of HA fillers they were rapidly metabolized when placed in the dermis. With the introduction of non-animal sources (NAS-HA), derived from the fermentation of Staphylococcus aureus coupled with the increased demand for nonsurgical cosmetic procedures, clinicians currently often rely on HAs as a product of choice for dermal fillers.6
HA is the main polysaccharide in the human dermis and consists of long unbranched alternating units of D-glucuronic acid and N-acetyl-D-glucosamine (Figure 1). This enables HA to
All currently available HA products in the United States are biodegradable fillers. Other biodegradable fillers include poly-L-lactic acid (PLLA, Sculptra Dermik Laboratories 2004, Fort Worth TX), and calcium hydroxyapatite (Radiesse Merz Aesthetics 2006, Franksville WI).4 HA was first utilized in dermal fillers in 1989 by Balazs and Denlinger and were derived from rooster crests.5 Until the addition of crosslinking agents with the first generation of HA fillers they were rapidly metabolized when placed in the dermis. With the introduction of non-animal sources (NAS-HA), derived from the fermentation of Staphylococcus aureus coupled with the increased demand for nonsurgical cosmetic procedures, clinicians currently often rely on HAs as a product of choice for dermal fillers.6
HA is the main polysaccharide in the human dermis and consists of long unbranched alternating units of D-glucuronic acid and N-acetyl-D-glucosamine (Figure 1). This enables HA to
