Injectable collagens: lost but not forgotten--a review of products, indications, and injection techniques.

Soft-tissue augmentation and three-dimensional volume replacement remain a cornerstone of facial rejuvenation. There has been an exponential increase in interest in dermal fillers. Science and technology have kept pace with this demand, and currently there is a wide range of options from which to choose. This is especially well illustrated by the recent introduction of an entirely new class of agents--the hyaluronans. The temporary fillers (the collagens and the Zyderm and CosmoDerm families), however, remain an excellent alternative, as they have a well-documented safety record, there are multiple formulations that make them very versatile, and the admixture of local anesthetic decreases the discomfort of injection.