The "gummy bear" or "form stable" implants (410 - Allergan, CPG - Mentor) have been some of the most awaited products in cosmetic surgery (these implants have only been available in a scientific study). They are more firm than the traditional "cohesive" gel implants. Both implant types tend to hold their shape, but the gummy bear implants are less "gel-like" and a bit more solid so they tend not to lose their shape even if ruptured. Cohesive silicone gel implants will maintain their shape if ruptured, but just less so than the others.
The "gummy bear" implants are "anatomic" meaning fuller on the bottom and thinner on the top with the attempt to mimic a natural breast shape. Thus, they are textured and need to stay in their proper place (they have a real top, bottom, front and back), and need a larger incision for insertion since they are less flexible.
The problem with this, is that normal breasts change shape depending upon the position you are in - standing or laying down. When you stand, natural breasts have a more "tear drop" shape, but laying down the natural breast will flatten out. These firmer, anatomic implants that are "form stable" are just that, "form stable" and will remain "anatomic" no matter what position you are in. Cohesive gel implants are round and smooth with no particular orientation (top, bottom, front or back). This allows for more freedom of movement without concern regarding the implants position. These implants come with the added benefit of taking different, appropriate shapes depending upon the position of the patient. Meaning, they flatten out when you lie down and take a more natural shape when you are standing.
Thus, it seems that for most women, traditional cohesive gel implants seem to be the most natural and reliable implant to produce the best result. The "gummy bear" implant will likely have a greater role in patients who have had trouble with capsular contracture as well as those women who desire breast reconstruction after mastectomy for breast cancer.
Vincent Marin, MD, FACS
San Diego Plastic Surgeon
