A filling is used to treat a small hole, or cavity, in a tooth.  To repair a cavity, a dentist removes the decayed tooth tissue and then fills the space with a filling material.

Causes

When decay-causing bacteria come into contact with sugars and starches from foods and drinks, they form an acid.  This acid can attack the tooth’s surface (enamel), causing it to lose minerals.  When a tooth is repeatedly exposed to acid, such as when you frequently consume food or drink high in sugar and starches, the enamel continues to lose minerals.  A white spot may appear where minerals have been lost.  This is a sign of early decay.  Tooth decay can be stopped or reversed at this point.  Enamel can repair itself by using minerals from saliva and fluoride from toothpaste or through the application of fluoride by a dentist or dental hygienist.  If more minerals are lost than can be restored, the enamel weakens and eventually breaks down, forming a cavity.  More severe decay can cause a large hole or even destruction of the entire tooth.  If tooth decay is not treated, it can cause pain, infection, and even tooth loss.

Treatment

Although it’s best to prevent a cavity, a cavity can be fixed.  There are several types of filling materials used to repair cavities, including tooth-colored (composite) fillings and silver-colored (amalgam) fillings.  Composite resin materials are increasingly used by dentists to fill teeth because many people prefer tooth-colored fillings and because composites continue to improve.  There are also treatments called crowns (or caps), used to repair badly broken-down teeth.  Crowns can be made of gold or other metals, porcelain, or stainless steel (usually used on baby teeth).  Generally, dental fillings and crowns do not last a lifetime and may need to be replaced.

Additional Resources

• U.S. Food and Drug Administration (FDA): Dental Amalgam

           Information about dental amalgam and other types of dental filling materials from the FDA.

• MedlinePlus: Amalgams

          The National Library of Medicine's collection of links to government, professional, and non-profit/voluntary                          organizations with information on dental amalgams.

• Exploring the Mouth’s Microbial Wonders
• Big Hopes for Little Teeth
• Your Mouth on a Chip