The three types of silicone gel-filled breast implants are as follows:

• One type is a single lumen implant that is prefilled by the manufacturer with a fixed volume of silicone gel.

• A second type is a double lumen implant with (1) an inner lumen prefilled by the manufacturer with a fixed volume of silicone gel and (2) an outer lumen that is filled during the operation with a fixed volume of saline through a valve.

• A third type is a double lumen implant with (1) an outer lumen prefilled by the manufacturer with a fixed volume of silicone gel and (2) an inner lumen that is filled during the operation with saline through a valve. This type of implant allows for adjustments of the saline volume after the operation.

A silicone gel-filled breast implant has a silicone rubber shell with the same general composition as shown in the Saline-Filled Breast Implants section above.

The filler is silicone gel that has the general composition of:

• silicone oil

• cured polymeric (large) silicones

• small amounts of uncured large and smaller silicones

• minute amounts (parts per million) of metals, including a metal catalyst (usually platinum). (A catalyst is something that causes a change in material.)

Alternative Breast Implants

An alternative breast implant typically has a silicone rubber shell with a filler other than saline or silicone gel. The filler material may or may not be a gel. An alternative breast implant may also have an alternative shell other than one made from silicone rubber.