Commonly considered the pioneers of modern day breast implants, Thomas Cronin and Frank Gerow developed the first silicone breast implants to be used in breast implant surgery. The first breast implants using this type was done in 1962. Silicone implants have arrived in 5 "generations", which are separated based upon the techniques in manufacturing. This was known as the first generation which were a tear drop shaped silicone rubber envelope filled with thick silicone gel. There was a Dacron patch on the outside of the shell to help reduce the rotation.