Biocompatible refers to the property of a material to elicit or perform without a negative host response (immune response or inflammation) in a specific application. In general, biocompatibility is measured on the basis of allergenicity, carcinogenicity, localized cytotoxicity, and systemic response. A material that is biocompatible can be used within the body without concerns regarding the long-term negative effects that may be associated with other commonly used, but not biocompatible, products. In dentistry, silver amalgam fillings have been a standard choice in tooth repair for many years. However, the mercury content in such fillings poses questions regarding toxicity for patients who have them. Recent advancements in dentistry have led many dental professionals and patients to biocompatible choices for filling materials such as plastics, resins, porcelain, or other composites. There are now also many dentists who work with only biocompatible materials to reduce the risk of toxicity to the patient throughout their life.