Dental fillings are placed to repair missing or damaged tooth structure caused through decay, excessive wear or physical injuries. In the past, back teeth were often filled with silver amalgam fillings, a material that provided an easy answer to damaged teeth. This material is still available, and used correctly, is a strong robust and relatively cheap material to use. However, alternative materials are available for tooth fillings these days, and should be given some consideration. Silver amalgam is an ugly material and the modern plastics, ceramics and "liquid glasses" allow for alternative fillings that look a whole lot better. Plastic filling materials are commonly used in small back fillings, as they do not yet have the strength for use in larger fillings. They are not much more costly than the old "silver" fillings, but look great. Ceramic or porcelain fillings can be used in both front and back teeth, and are much stronger than the plastic fillings, and assist in "bonding" together, small fracture lines that occur in teeth. The ceramic fillings are more expensive than the old silver fillings, but are stronger and a better alternative than the "plastic" alternatives. Ask your dentist about the modern ceramics that are specially treated to increase their strength. "Liquid glass" fillings, or glass ionomer fillings, are used where teeth have been damaged near the gum line. These fillings are relatively strong, but flexible and have an anti decay effect on the surrounding tooth. They are commonly used for areas where brushing with too hard a brush has caused "erosion" areas. Plastic, ceramic and "liquid glass" fillings are those often referred to when people talk about "bonding".