Dermal fillers have continued to innovate over the past 2 decades.
Initially, we only had collagen derived from pigs or cows that lasted a small period of time (3 months at most) and carried a huge allergenicity profile. These type of fillers had to be allergy tested prior to use secondary to the high degree of reactivity.
Realistically, fillers are actually placed subdermal instead of dermal in most cases.
Restylane and Juvederm were among the first dermal fillers that were FDA cleared around 2006-2007.
Since then, the characteristics of fillers have been critically evaluated to see how what type of filler would withstand shear forces of movement and how the filler can glide and integrate better with the tissue to give the most natural type of result.
Two such fillers have come to market in the past 3 years that satisfy the newer criteria of "natural movement".
Restylane with Xpression technology allows for the filler to move with patients facial movements to give a seamless finish. In this category is Restylane Refyne, Restylane Kysse, Restylane Defyne and Restylane Contour. We use them all in the practice with a heavy emphasis on Defyne and Contour.
RHA is another filler (made by Revance who is soon to launch the first 6 month Tox called Daxxify). RHA stands for resilient hyaluronic acid, in that there are longer chains of HA which mimic our own natural HA and the product as well is resilient to shear and compression forces which is similar to how our on tissue interacts to these forces.
These two filler lines have become popular in our practice secondary to the natural results they achieve.