According to Dr. Daniel Meyer, director of the American Dental Association Division of Science, "To make the best overall decision on a treatment--an informed decision--patients should know the options, the benefits and limitations of each restorative choice." He adds, "dentists are the primary source of that oral health information."

Restorative filling materials are used to "fill" the hole that is left in a tooth after your dentist removes decay from the tooth. Silver amalgam, composite resins, and glass ionomers are commonly used. They are usually placed in one visit.

Sometimes the best dental treatment for a tooth is to use a restoration that is made (cast) from a mold. These custom-made restorations can be a crown, an inlay or an onlay. A crown covers the entire tooth to strengthen and improve its appearance. An inlay fits within the contours of the tooth. An onlay is similar, but it also covers some or all chewing surfaces of the tooth.

These restorations usually require two appointments. In the first visit the tooth is prepared for the restoration and an impression is taken. A temporary covering (or filling) is placed to protect the tooth. The restorations are made (using the model created from the impression) of various alloys used for crown, inlays, and onlays and/or porcelain or porcelain-like materials.

Amalgam

Amalgam (Silver) fillings are made of a mixture of mercury and other metals, and remain the single most commonly used filling material. Dental amalgam is used for a number of reasons, including its durability, longevity and ability to withstand the intense pressures of chewing. It is durable, easy to use and relatively inexpensive in comparison to other materials and therefore remains a valued treatment option for dentists and their patients.Other materials have drawbacks. Gold is an effective material, but it costs more than amalgam. Tooth-colored ceramics and porcelains provide a natural appearance, but aren't as resistant to stress or fracture and have to be replaced more often. New resorative materials continue to be developed that may someday equal or exceed the benefits of amalgam.

Dental amalgam is the most thoroughly researched and tested restorative material among all those in use. Studies of dental amalgam in tooth restorations have been conducted worldwide for more than 100 years. These studies have failed to find any link between amalgam restorations and any medical disorder. Amalgam continues to be a safe restorative material for dental patients.

Some have raised concern about amalgam because of its mercury content. The concern is intuitive but unfounded. Although mercury by itself is classified as a toxic material, the mercury in amalgam chemically combines with other metals to render it stable and therefore safe for use in accepted dental applications.

As questions have risen about its safety related to its mercury content, they have been answered to the satisfaction of the major U.S. and international scientific and health bodies, including the National Institutes of Health, the U.S. Public Health Service, the Centers for Disease Control and Prevention, the Food and Drug Administration and the World Health Organization, among others.

Allergic reactions to the mercury in amalgam are very rare. Fewer than 100 cases have ever been reported. Mild symptoms of the allergic reaction, similar to typical skin allergies, usually disappear in two to three weeks.

Stories of overnight cures form serious diseases when amalgam fillings are removed are not supported by scientific evaluation. The Food and Drug Administration has concluded that amalgam causes no demonstrated clinical harm to patients and that removing amalgam will not prevent adverse health effects or reverse the course of existing diseases.

The American Dental Association remains committed to providing the best possible information on oral health, based on sound science, to the profession, government and the public. In keeping with that commitment, we continue to believe that dental amalgam is one of the safe choices for patients needing restorative treatment to consider with the advice and guidance of their dentists.

Composite resins are plastic materials (made of glass and resin) that are used both as fillings and to repair defects in the teeth. They are tooth-colored, making them difficult to distinguish from the natural tooth.

Composites are often used on the front teeth where a natural appearance is important. Occasionally, they are used on the back teeth when the restoration is small, or in cases where it may be visible.

Composite resins are usually more costly than amalgam fillings and may be less durable when used on the back teeth.

Glass Ionomers

Glass ionomers are tooth-colored materials made of fine glass powders that are used to fill cavities, particularly those on root surfaces. If gums recede, tooth roots can become exposed and their cementum covering is easily worn away. Because the underlying tooth root is dentin (a softer tissue than enamel), it is more prone to decay.

Like composite resins, glass ionomers can bond to dentin to cover the exposed area. Glass ionomers contain fluoride, which is released slowly to help prevent tooth decay.

Casting Alloys

Custom-made dental restorations, such as crowns, inlays, and onlays, are often made of a combination of metals called an alloy. An alloy may contain precious metals, like gold and palladium, or non-precious metals such as nickel or chromium.

Custom-made restorations are durable, but do not closely match normal tooth colorations unless covered by a material such as porcelain.

Porcelain

Porcelain is a natural-looking restoration made of a very strong glass. It is used to make veneers, crowns, inlays, onlays or the artificial teeth in bridges and dentures. Porcelain can be blended to closely match the color of adjacent teeth.

Crowns can be made entirely of porcelain or made with a metal alloy inner lining, which strengthens the crown. In certain cases, porcelain, which is harder than enamel, can wear opposing teeth.