Contemporary fillings are generally tooth-colored, composite materials made of glass or quartz and resin. These materials may be used as fillings and also to repair defects in teeth. Because these are tooth-colored, they are virtually invisible and perfectly suited for repairs on front teeth. Back teeth may require a stronger filling, like a metal amalgam or porcelain in order to withstand the high chewing loads and pressure in that area of the mouth. Fillings are placed in the tooth when a cavity is found and prepared and usually require only one visit. Talk with your dentist about which fillings they prefer to use and why. If you are concerned about both appearance and oral function, your dentist may be able use a tooth-colored material for fillings, even for back teeth.