The Science of Cohesivity and Elements of Form Stability.

Silicone gel implants vary in terms of gel cohesivity and form stability. Various degrees of gel cohesivity are obtained by varying the density of crosslinking between silicone polymers. Less cohesive gels are less crosslinked, are more elastic, and have a softer feel while more cohesive gels more crosslinked, are less elastic, and have a firmer feel. When a highly cohesive gel is able to maintain its intended distribution within an implant, the gel is referred to as being form stable. Thus, a form-stable implant is able to retain its designed shape and dimensions in any position. Gel cohesivity and form stability influence breast shape, softness/firmness, and in vivo implant performance and an understanding of these parameters is critical to implant selection.