Direct restorations - require 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; glass ionomers; resin ionomers; and composite (resin) fillings.
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.
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.
Composites are tooth-colored materials made from acrylic resin filled with tiny glass or quartz particles. Composites are more aesthetic, stronger, and more durable than glass ionomers and can be used on biting surfaces. They are bonded to the tooth.
Indirect restorations. These require two or more visits and include inlays, onlays, veneers, crowns, and bridges. These are constructed with gold, base metal alloys, ceramics, or 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 place the new restoration into the prepared area. Some offices use newer technology 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, saving the patient a return visit.
For an indirect restoration, a dentist may use an all-porcelain, or ceramic, application. 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 or inlays and onlays. Less expensive alternatives to gold are base metal alloys that can be used in crowns and are resistant to corrosion and fracture. Indirect composites are similar to those used for fillings and are tooth-colored, but they are not as strong as ceramic or metal restorations.