Injectables are surging in popularity, thanks to their myriad benefits. Now a standardized scale of filler cohesivity, or how well the material sticks together, can help plastic surgeons use the best filler for each client. The researchers developed a standard test for comparing the cohesivity of HA dermal fillers. Samples of each filler gel were dyed, then squeezed into water and stirred using automated technology. A panel of plastic surgeon and dermatologist specialists experienced in using HA fillers then rated each sample's cohesivity on an original five-point scale, known as the Gavard-Sundaram scale.
Fillers are used to reduce facial lines and wrinkles; and restore volume, fullness and a youthful shape to the face, among other purposes. A wide range of HA fillers are available, and plastic surgeons try to match their individual properties to the purposes for which they will be used. But previously there was a lack of scientific data to support this matching process, including the rheologic (flow-related) properties of the various available products.
Researchers tested six FDA-approved fillers, and cohesivity scores varied across the full range of the scale: from "fully dispersed" to "fully cohesive." Cohesivity was rated high for one product, medium to high for three, low to medium for one, and low for one.
The researchers believe that having comparative data on cohesivity—as well as other rheologic properties, such as elasticity and viscosity—is an advance that can make dermal filler procedures more sophisticated and successful. This information will be increasingly useful as new FDA approvals increase the availability and variety of filler products.