Implants differ by surface, cover, filler and form – shape.
Surface of implant
Most implants have surface made of silicone, with exception of implants covered by a thin titan layer (no more on the market) and implants with polyurethane surface. They are rarely used because they grow together with surrounding tissue so strongly that they are practically irremovable.
The surface can be smooth or rough. A whole range of studies affirm that implants with rough surface have lower appearance rate of capsules (Baker III and IV). Roughness of the surface is different at different manufacturers and all of them declare their surface to be the best protection against capsules.
Cover of implant
The cover of implant is always made of silicone. It can have one or more layers. Theoretical advantage of covers with more layers was not clinically approved.
Content of implant
Implants contain either silicone, physiological solution or hydrocoloid fluid. Implants with hydrocoloid fluid are rarely used and it is therefore not necessary to describe them in detail.
In Europe are used 96% of implants filled by silicone and approximately 3% by physiological solution. Aesthetic results of implants filled by physiological solution are always worse than implants filled by silicone.
Liquid silicone was used in the past, nowadays it is so called cohesive gel (silicone builds long chains). Advantage of this filling is its relative tough consistency – it does not leak if the cover is damaged (silicone bleeding). Disadvantage – very relative – it is necessary to make longer incisions because of its higher toughness. Implants are filled from 80 to 100%, those with lesser quality contain even smaller amount of silicone. Insufficiently filled implants, above all implants with rough surface represent the main reason of rippling on the skin under the implant. Original implants were round and even today mostly implants with this shape are used.
Shape of the implant
Implants with oval – anatomic shape appeared already in the last two decades of the last century, however without success. In the nineties, company named McGhan – now Inamed started a massive campaign aimed on using these implants. Nowadays this company offers 16 different shapes of implants.
Theoretical advantages of oval implants are obvious – more natural shape, it should form the breast better when the chest is longer or breasts slightly sagging. Disadvantage is their relatively high price, they must be placed exactly, the pocket created for the implant must not be too large – the implant could turn around. However in practice we see that even small pressure changes oval shape into round and the whole effect can be only minimal or even none.
The question of lasting quality of implants, so heavily discussed on these pages, can not be answered explicitly. It is not true that half of the implants must be replaced as early as after 5-8 years. But it is also not true that modern implants do not have to replaced at all. High quality implants last definitely longer than implants with interior quality. Material of implants wears off, same as any other material, and its durability depends above all on its mechanical stress. Implants of women who exercise, play sports and above all tennis, wear off faster. The cover thins unevenly and small cracks appear. These cracks cause the silicone to flow out of the cover and the breast shape to change. This danger does not exist in case of cohesive gel. In my opinion, the real cause of the implant rupture is its damage during the operation. The biggest study concerning implants defines the implant rupture as the cause of reoperation in first 6 years at 1% of patients! Fa mentor – more than 80.000 patients).
Also the Inamed company provides 10-year guaranty for the implants with cohesive gel.
This short review shows how many technical factors influence the choice of implants. The most important of them is however the human factor – experience of surgeons and their aesthetic feeling.
MUDr. Michael Entner