Both saline-filled breast implants and silicone-filled implants have an outer shell composed of silicone elastomer. This shell is basically a flexible envelope that contains the implant filling. In the case of some anatomically shaped implants, the shell also gives the implants shape. Some models of implants have a "double lumen." This is an elastomer envelope inside of another elastomer envelope (sort of like double-bagging your groceries) which may reduce the risk of implant rupture.
Look for a board-certified plastic surgeon from the American Board of Plastic Surgery who has extensive experience performing rhinoplasties and other areas of facial plastic surgery. You can search for one by geographic region on A Board Certified Plastic Surgeon Resource. Though they typically charge higher fees, these surgeons have all undergone intensive surgical training and can help ensure that you receive the best possible treatment.