Fillings, known clinically as amalgams, are synthetic materials that are used to restore a portion of a tooth damaged by decay or traumatic injury. There are different types of materials used to fill cavities, including gold and metal alloys.

Conventional amalgams are the silver-colored material many people have had placed in their teeth following treatment of a cavity. Many amalgams are actually a combination of various metal alloys, including copper, tin, silver and mercury. Mercury, a binding agent used in amalgams, has come under scrutiny lately by some health officials who claim it may cause long-term health problems.

The American Dental Association cautions that emotional reports claiming amalgam is responsible for a variety of diseases are confusing and perhaps even alarming people to the point where they will not seek necessary dental care. Moreover, the ADA maintains that there has been no scientific evidence to show that amalgams are harmful because the miniscule amounts of mercury are so stable, they present no risks to humans. There have been rare cases of patients developing allergic reactions to amalgams.

There are alternatives to conventional substances used in amalgams, such as gold and metal alloys. These include materials made from porcelain and composite resins, which are colored to match natural tooth enamel. Unfortunately, few materials can match the strength and durability of conventional dental amalgam and may need more frequent replacement.

• Composite fillings - As stated, composite fillings are just what the name implies: a mixture of resins and fine particles designed to mimic the color of natural teeth. While not as strong as dental amalgam, composite fillings provide a pleasing aesthetic alternative. Sometimes composite resins need to be cemented or bonded to a tooth to allow for better adhesion.
• Ionomers - Like composite resins, these materials are tooth-colored. Ionomers are made from a combination of various materials, including ground glass and acrylic resins. Ionomers are typically used for fillings near the gum line or tooth root, where biting pressure is not a factor. They are more fragile than dental amalgam, however. A small amount of fluoride is released by these compounds in order to facilitate strengthened enamel in the affected area.
• Porcelain (ceramic) - These materials are usually a combination of porcelain, glass powder, and ceramic. Candidates for porcelain fillings are typically crowns, veneers, and onlays and inlays. Unlike ionomers, porcelain fillings are more durable, but can become fractured if exposed to prolonged biting pressures.