ABSTRACT
Soft tissue augmentation has been popular for restoring the loss of volume and elasticity of the face for over 20 years. Bovine collagen and autologous fat transplantation remain two of the most widely used filler substances. Both have their advantages and drawbacks. Because the general consensus among physicians is that an ideal filler substance is yet to be developed, both human-and nonhuman-derived products continue to be developed and evaluated.
