Other implants , including those filled with a soy products, are under investigation at this time. Saline filled implants are available with two types of surface, rough and smooth. The traditional implant has a smooth surface and was found to have a higher rate of hardening of capsule. The smooth implant is now used mainly under the muscle. A rough or textured implant is commonly used above the muscle because it seems to reduce the risk of capsular hardening .
Some surgeons believe that the anatomical implants produces a more natural shape to the breast.
Other surgeons disagree. Some believe that anatomical implants may have an increased risk of folding of the silicone envelope which may lead to tearing. The implant can be placed under the gland of the breast or more deeply under the muscle of the chest wall. One position is not better than another. The position must be decided on an individual basis.