Silver amalgam fillings are composed of 50% mercury and 50% silver alloy and eventually need to be replaced. It may surprise you to know that the average life span of a silver filling is five to eight years. Your dentist can tell you when they appear to NEED to be replaced due to leakage, breakdown or recurrent decay. If your concern is strictly COSMETIC, there are many new methods available to replace the fillings with beautiful, functional long lasting restorations. Such things as white filling materials, porcelain inlays, crowns(adds strong top to teeth) and veneers may be used to give you the smile you are seeking. There is currently a great deal of interest in new reinforced hybrid materials. These beautiful resin materials may be reinforced with fibers, similar to fiberglass, and used in very conservative inlays and bridges without having to grind away a whole healthy tooth.