While many types of implant materials have been tried for use in the face, only a limited few have enjoyed a history of good clinical success. Today’s facial implants are composed of the synthetic polymers dimethysiloxane (silicone), polyethylene (Medpor), polytetrafluoroethylene (Gore-tex), and polyester. (mersilene)
The use of solid silicone rubber (solid, not liquid silicone) have been used as facial implants material for nearly four decades. Silicone implants are by far the most type that are used in the face. Silicone is a essentially a form of plastic created from interlinking silicon and oxygen into a compound known as dimethylsiloxane (SiO(CH3)2) . Its chemical advantage is that it is very resistant to breaking down to the very strong and stable silicon-oxygen bonds. When converted into a polymer and vulcanized, a solid silicone rubber which is elastic and very flexible is formed. When shaped into a facial implant, it has the advantages of ease of placement through small incisions due to its flexibility, can be easily cut and shaped if necessary during surgery, and are of low cost.
Like the material used in coats and shoes, Gore-Tex has been used as a facial implant since 1994. It has been used as more traditional shaped implants for the cheeks and chin as well as soft tubes to be used right under the skin as a soft tissue filler. Gore-Tex is really polytetrafluoroethylene, a fluorocarbon which has a carbon ethylene backbone to which is attached four fluorine molecules (PTFE). The bonding of highly reactive fluorine to carbon creates an extremely stable biomaterial which the body can not break down due to the lack of any known human enzyme to disrupt the fluorine-carbon bonds. The material is extremely flexible and is easily cut and shaped. The fabrication of Gore-Tex results in small interconnected pores on its surface and throughout the material which may allow for some tissue ingrowth. The advantage of tissue ingrowth is probably more theoretical than of any practical significance.
Medpor, known chemically as polyethylene (PE) has been used in the face for over a decade. It is different than Gore-Tex (PTFE) as it has no fluorine molecules in it. The chemical structure may be simple but it has a very firm consistency that makes it the hardest facial implant used. It comes in different facial shapes and sizes and, although it can be shaped, it is not easy. The material does have small channels through it which allows for tissue ingrowth into it. That makes it harder to remove if necessary due to the sticky scar.
Mersilene is a knitted plastic mesh material most commonly used to fix abdominal hernias. It has been historically used in facial surgery where it has been used as a chin implant. The mesh material is rolled onto itself, shaped, and then sewn together to create the implant. Because the implant is a mesh, it has lots of holes in it for tissue ingrowth. The few surgeons who use mersilene do it because they like to fashion their own implants and can do so at a lower cost than buying other off-the-shelf implants.
Your plastic surgeon may use any of these materials for your facial implant surgery. While silicone rubber is the most commonly used, all other materials are acceptable and very well tolerated by the face. Tissue ingrowth into facial implants with pores or channels, while theoretically appealing, has not been proven to offer any advantages over completely solid silicone rubber implants.
Dr. Barry Eppley
Indianapolis, Indiana