Bridges are natural-looking dental appliances that can replace a section of missing teeth. Because they are custom-made, bridges are barely noticeable and can restore the natural contour of teeth as well as the proper bite relationship between upper and lower teeth. There are several types of fixed dental bridges (cannot be removed), including conventional fixed bridges, cantilever bridges and resin-bonded bridges. Some bridges are removable and can be cleaned by the wearer; others need to be removed by a dentist. Porcelain, gold alloys or combinations of materials are usually used to make bridge appliances. Appliances called implant bridges are attached to an area below the gum tissue, or the bone.