The world was introduced to the first generation of silicone gel implants in 1962. Created by Cronin and Gerow, these original implants were silicone-based but have continuously evolved ever since.
Saline implants quickly followed. Developed in 1965 by Arion in France, they gradually became an alternative to the silicone breast implant. Over the years, we’ve seen the development of 5 different generations of breast implants, each one improving on its antecedent in an attempt to address the shortcomings of the previous version. The fourth- and fifth-generation breast implants are the ones we currently see offered on the market.
Saline-filled breast implants were initially developed as a tissue expander. It was later realised that this saline-filled device could also be used as an implant itself. This effectively made it a direct alternative to the silicone implant.
The advantage of saline implants is that they can be inserted through a smaller incision. This is because the volume can be adjusted during surgery to fine-tune any volume asymmetry a patient has.
A disadvantage, however, is they felt more like a water balloon in comparison to the silicone breast implant which was more viscous and more like natural breast tissue. However, in patients with sufficient soft tissue coverage over the implants, the difference between saline and silicone implants was minimal.
The body of each Implant is built as a two-component prosthetic, filled either with saline or silicone gel. They are surrounded by a layer called the “shell” which in essence is a solid silicone form that protects the core of the silicone gel implant. To clarify, silicone gel is a mixture of semi-inorganic polymeric molecules. In other words, it feels and looks like an oily fluid. To give an example, you can see silicone in the lubricants they use with most medical devices.
The first generation of silicone-filled implants were teardrop shaped. They had several Dacron fixation patches to help maintain their proper position and avoid movement or spinning.
The main problem experienced with these original breast implants was a relatively high contracture rate. This was believed to be due to the quality of both the shells and the gel. As a result, the second-generation silicone implants were developed in the 1970s.
The second generation implant had a thinner, seamless shell, no Dacron patches and were filled with a less viscous silicone gel for a more natural feel. Their general design was also changed from a shaped to a round implant. Unfortunately, these thinner shells led to complications, namely, there were leaks and ruptures throughout the breast. This was because of the thinner shell and lower viscosity of the silicone gel itself.
Thus in the 1980’s, the third generation of silicone implants was developed. These implants focused on increasing the strength of the implant shell, decreasing its permeability to silicone molecules, and to reduce the risk of implant rupture.
This was done by altering the shell into a multi-layered silicone elastomer. With every generation, they came up with new solutions to fix the problems that arose in the last. The 4th and 5th generation are what we see being used today as the standard for breast enhancements.
Silicone is also a mixture of semi-inorganic polymeric molecules, composed of varying length chains of polydimethylsiloxane [(CH3)2-SiO] monomers. The physical properties of silicones are controlled. They are regulated by the average polymer chain length and the degree of cross-linking between these chains.
Liquid silicones are relatively short chains with very little cross-linking. Silicone gels are created by increasing the length of the polymer chains or the degree of cross-linking.
A ‘form-stable’ or better know as ‘gummy bear’ silicone is one where enough filler cross-linking is achieved to the degree that the silicone gel will maintain its dimensions and form.
Extensive chemical cross-linking of the silicone gel polymer produces a solid form of silicone. This is referred to as an elastomer, something with a flexible, rubber-like quality. They are used for the manufacture of facial implants, tissue expanders, and the outer shell of all breast implants.
The shell has undergone various modifications over time, such as barrier layers and a triple-shell layer which has led to safer implants.
The surface of the actual breast implants can now be ‘smooth’ or ‘textured’. This texture has been created in an attempt to minimise and disrupt the formation of capsular contracture and prevent implant hardening.
The evolution of textured implants began with a simple polyurethane-coating. This was implemented as it had a significantly lower capsular contracture rate compared to regular silicone breast implants.
These polyurethane-coated implants were eventually taken off the US market due to concerns regarding the difficulty of their complete removal from the body. There is also a theoretical worry that polyurethane could be carcinogenic.
Polyurethane is thought to undergo partial chemical degradation, releasing compounds that may become carcinogens in animals. While they have not been shown as human carcinogens, it was decided that it was a risk not worth taking.
Thus, in the 1980s surface texturing was created as an alternative method to attempt to lower the risk of capsular contracture.
In 1992, the FDA (Food Drug Administration) imposed a moratorium on silicone breast implants. This was to be until breast implant manufacturers were able to provide long-term data proving their devices were safe. As a result, the fourth and fifth-generation breast implants were developed through much more rigorous testing.
As a result, there was no availability or access to the gel implants from 1992-2006 (in the US only, in Europe and Asian silicone implants continued to be used). This is when saline breast implants entered the limelight as a favoured alternative for the US. The 5th generation implants were still available through international spots and in Canada by a special access program of the Medical Device Bureau of Health Canada in 2000.
These newest implants comply with the strongest American Society for Testing Methodology standards and FDA-influenced criteria for shell thickness and gel cohesiveness. These implants also offer a wider variety of sizes, shapes, and textures. The shell, surface, and filler substances are much more advanced, longer lasting and less prone to damage.
The 5th generation of the breast implant corresponds to a very natural shape and a textured shell which gives the breast that realistic feel. It’s attached to the breast tissue and has very little chance of complications than the previous generations. It also retains its shape in various positions thanks to the flexible silicone gel.
All through time, there have been these alterations and improvements to ensure that the highest quality of breast implants for any woman is available today on the market. These modifications of feel, look and materials were not only because of the manufacturers’ studies and clinical trials but also and primarily thanks to feedback from the many clients who used these enhancements.
More importantly, safety in silicone breast implants is now first-rate. Instances and reports of women expressing concerns regarding autoimmune reaction from breast implants are rare. Numerous studies have also shown there is no difference in the rate of autoimmune diseases in patients receiving either silicone or other types of implant. Furthermore, a meta-analysis of 87,000 women has revealed no association between silicone breast implants and connective tissue disease.