Dental Fillings are used to replace the parts of the tooth that have been lost, due to a number of reasons. These include wear and tear, decay and accidental damage. There are a variety of different materials that can be used for filling teeth. The most common type of filling is dental amalgam. This is made from a mixture of mercury and different metals. Composite or white fillings are less obvious and more natural looking. They are almost identical to the natural tooth.