When breasts are too small to fill a shirt or blouse, they are often described and perceived by women as deformed. 

Since 1962 about a million women have had breast augmentation, with 90% of them pleased with the results. There have been some severe problems with silicone gel in the past. Those problems are not related to any disease or immune phenomenon. Those problems are related to the fact that silicone gel is chemically inert and if an implant should break, it cannot be easily removed from the body. When silicone gel implants are ruptured, for instance as in an automobile accident when the seat belt in a collision impinges on the implant and breaks it that gel because it is moldable and movable can be compressed and propelled out of the area of the breast into the surrounding tissue. 

Weeks or months later, that can be felt as a nodule, and the patient of course, is quite alarmed because they think they have a tumor that can only be proven by biopsy. Gel can also shoot up the arm, cause lumps that can be misdiagnosed causing unnecessary removal of tissue, and lumps that may interfere with x-rays. In addition, the silicone gel can be forced down the nerves of the arm and because it is chemically inert it cannot be removed except by removing the nerve which, of course, would leave a terrible deficit.

Therefore, when reasonable alternatives were discovered, many surgeons stopped using silicone get and patients, when confronted with a choice between a water-soluble jelly-like material such as Novagold or Mistigold, overwhelmingly choose that material over silicone gel. 

At the present time, we have three flavors of breast implants available throughout the world - saline, silicon and various vegetable oils such as soybean and peanut oil. 
Of the three variations, they each have certain characteristics.