Hyaluronic Acid Crosslinking
Every injectable with the Juvederm brand name is derived from Hyaluronic Acid (HA). HA occurs naturally in the skin and dermis and maintains a youthful, expanded hydrated quality. HA molecules in fillers, are cross-linked for stability and result in gels of different consistencies. The strength of a gel is dependent on the total number of crosslinks (both chemical crosslinks and natural entanglements). One important aspect of gel strength is Cmin. This is the concentration of HA in the fully swollen gel in an excess of the solvent. The stronger the gel the better is the lifting capacity and the expected duration. Stronger gels swell less and have a higher value for Cmin. G* is the complex modulus measured by rheology. It is a measure of the total resistance to deformation. Stronger gels have a higher resistance to deformation and a higher value for G*.
Voluma XC is the longest lasting and the thickest of the Juvéderm suite of products. Voluma XC has the highest lifting capacity.
Hylacross versus Vycross
Hylacross technology fillers such as Juvederm XC and Juvederm Ultra, have crosslinked molecules of the same weight. Vycross technology fillers such as Volbella, Voluma, and Vollure are made of crosslinked HA molecules of different weights. All are pre-packaged containing Lidocaine or Xylocaine, which is a local anesthetic, hence the ‘XC’ designation. Vycross technology is less hydrophilic which means that it attracts less water and therefore results in less swelling. All injectables require an effective therapeutic volume to obtain a measurable result. Undertreating with an inadequate volume may result in dissatisfaction and patients should understand that using an optimal amount of filler will give the best and the most durable result.
Voluma XC is injected close to the facial bones to primarily enhance the cheeks, chin and jawline. It can be placed right along the bone or into the deep fat compartments, usually in the cheek area. Voluma XC can last, in my experience, from 6 months to a year. Length of action is subjective depending on what is considered optimum correction, which can affect the need for more treatments. Most treatments start with a minimum 2 cc. or two syringes.
Juvederm XC and Juvederm Vollure are both suitable for the treatment of nasolabial folds and marionette lines. Vollure is longer lasting than Juvederm XC (up to 18 months versus six to 12 months) and it spreads less readily than Juvederm XC. Dr. Kirwan prefers Juvederm XC for lip augmentation.
