Because your body tissues need to cover the implants adequately to provide a safe home for them.
When your tissues are stretched too far and become too thin, then the implants have a greater tendency to harden and even become painful. This is far more common with silicone gel implants.Moderate breast implant sizing is important in making long term success much more possible.
The author's preference is to use saline-filled implants unless problems warranting consideration for silicone gel come into view - rippling in particular. Patients considering silicone gel implants are informed that there is some uncertainty with silicone gel. Long term risks for re-operation and distortion from scarring (some of which may not be repairable) are higher when silicone gel implants are used. This philosophy has yielded a majority of patients with soft breasts for ten years and more after surgery most with their original saline implants still in place.
© John Di Saia MD
... an Orange County California Plastic Surgeon
Serving Southern California since 1997 * (949) 369-5932