While the injection of botulinum toxin is the number one non-surgical cosmetic treatment according to the American Society for Aesthetic Plastic Surgery, the fifth most popular non-surgical cosmetic procedure is the injection of hyaluronic acid. Hyaluronic acid dermal fillers provide fullness to areas of the face and hands that have lost volume due to subcutaneous fat loss. They also fill in fine lines or deep wrinkles. Hyaluronic acid dermal fillers have gained popularity since they do not cause a loss in muscle control like botulinum toxin injections. They are also reasonably long lasting without being permanent. There are a number of dermal fillers containing hyaluronic acid that are available on the market. Brand names of hyaluronic acid include Restylane, Juvaderm, Captique, and Prevelle. Hylaform and Hylaform Plus, though, were the first hyaluronic acid fillers available for use in the United States. Almost all hyaluronic acid dermal fillers are produced through the fermentation of specially engineered bacteria, but Hylaform and Hylaform Plus are different. These agents are made from the combs of roosters in which the hyaluronic acid has been extracted and purified. The hyaluronic acid is cross-linked with a compound called divinyl sulfone in its preparation. The amount cross-linking achieved in this process is about 20%. This cross-linking is believed to slow down the body’s ability to break down the material thus making it last longer in the skin. The major difference between Hylaform and Hylaform Plus are the size of the individual particles that are injected. Hylaform is composed of 500 micron particles (half a millimeter across) while the particle size in Hylaform Plus is 750 microns. Because...
