What are fillings?

Fillings are special materials that your dentist places in or on your teeth to repair tooth decay (cavities) or defects on the tooth surface. Fillings (also called restorations) restore the tooth to form and function. Advances in dental materials and techniques provide new, effective ways to restore teeth.

There are several different types of restorations, including direct and indirect restorations.

Direct restorations

These need a single visit to place a filling directly into a prepared cavity. Materials used for these filings include:

  • Dental amalgam, also known as silver fillings

  • Composite (resin)

  • Glass ionomers

  • Resin ionomers

Amalgam fillings have been used for decades, and have been tested for safety and resistance to wear. Dentists have found amalgams to be safe, reliable, and effective for restorations.

Composite fillings are the most esthetic of the tooth-colored restorations. They are made from acrylic resin filled with tiny glass or quartz particles. They are strong, safe, and reliable. They are not quite as strong or wear resistant as amalgam but stronger and more durable than glass ionomers and can be used on biting surfaces. They are bonded to the tooth.

Glass ionomers are tooth-colored materials made from fine glass powders and acrylic acids. These are used in small fillings that do not have to withstand heavy pressure from chewing. Resin ionomers are made from glass with acrylic acids and acrylic resin. Both of these types of glass ionomers chemically bond to the mineral in the tooth.

Indirect restorations

These need two or more visits and include inlays, onlays, porcelain and resin veneers, crowns, and bridges. These are constructed with gold, base metal alloys, ceramics, porcelain fused to metal or specially formulated composites. At the first visit, a dentist will prepare the tooth and make an impression of the area that will be restored. At the second visit, the dentist will cement the new restoration into the prepared area. Some offices use newer technologies called CAD/CAM (computer-aided design/computer-aided manufacturing) that allows them to produce the indirect restoration in the office and deliver it at the same appointment. This saves the patient a return visit.

For an indirect restoration, a dentist may use an all-porcelain, or ceramic, material. This material looks like natural tooth enamel in color and translucency. Another type of indirect restoration may use porcelain that is fused to metal, which provides additional strength. Gold alloys are used often for crowns, foundations for porcelain fused to metal crowns or inlays and onlays. Inlays and onlays can also be made from ceramic or composite resin materials. Less expensive metal alloys may be used as alternatives to gold for all-metal crowns and porcelain fused to metal crowns. Indirect composites are similar to those used for fillings and are tooth-colored, but they are not as strong or wear resistant as ceramic or metal restorations.

Online Medical Reviewer: Kapner, Michael, DDSWalton-Ziegler, Olivia, MS, PA-C

Date Last Reviewed: 12/1/2017

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