Today patients have some leeway in their choice of fillings. A dental filling is a material that is soft when placed and hardens in place to repair small to medium areas of a tooth. This means it can be done in a single visit. There are two materials that fit this definition: amalgam and composite. Amalgam is a metal alloy containing mercury, in the case of dental amalgam it is about a fifty-fifty mixture of mercury and a metal alloy largely composed of silver. Composite is a hybrid material composed of acrylic with a reinforcing material such as quartz or boron. There are several differences in these materials besides the color. Amalgam has been around for over a hundred years and is a forgiving material to work with. It can be placed in a contaminated field (where there is saliva or blood). This makes it a better choice for small children or other situations when the field can’t be kept dry, or when decay extends below the gumline. Since it takes some time to harden, it can be shaped once placed. This is important in forming surfaces in between teeth. Composite needs a clean, dry field in order to be placed or leakage and new decay can appear in fairly short timeframe. Composites have a much higher rate of post-operative sensitivity than amalgam. However, in the proper circumstances, composite has the advantage of bonding to tooth surface without the need to cut a dovetail preparation into the tooth. Composite fillings are a little more expensive to place because of the time and greater difficulty in placing, yet most insurance companies will only make allowance for the cheaper alternative. This means a larger out of pocket expense falls to the patient. What does all this mean? Each material has it’s own pluses and minuses. Next time you need a filling, talk with your dentist to determine which material best meets your needs.