Dental caries

Alternative names:

cavities, tooth; dental cavities; tooth decay

Definition:

A disease of the teeth resulting in damage to tooth structure.

Causes, incidence, and risk factors:

Dental caries (tooth decay) is one of the most common of all disorders, second only to the common cold. It usually occurs in children and young adults but can affect any person. It is the most important cause of tooth loss in younger people.

Bacteria are normally present in the mouth. The bacteria convert all foods-especially sugar and starch-into acids. Bacteria, acid, food debris, and saliva combine in the mouth to form a sticky substance called plaque that adheres to the teeth. It is most prominent on the grooved chewing surfaces of back molars, just above the gum line on all teeth, and at the edges of fillings. Plaque that is not removed from the teeth mineralizes into calculus (tartar). Plaque and calculus irritate the gums, resulting in gingivitis.

The acids in plaque dissolve the enamel surface of the tooth and create holes in the tooth (cavities). Cavities are usually painless until they grow very large inside the internal structures of the tooth (the dentin and the pulp at the core) and can cause death of the nerve and blood vessels in the tooth, resulting in tooth abscess.

Acids begin to dissolve tooth enamel within 20 minutes after eating, the time when most bacterial activity occurs. Untreated tooth decay can result in death of the internal structures of the tooth with eventual loss of the tooth.

Dietary sugars and starches (carbohydrates) increase the risk of tooth decay. The type of carbohydrate and the timing of ingestion are more important that the amount. Sticky foods are more harmful than nonsticky foods because they remain on the surface of the teeth. Frequent snacking increases the time that acids are in contact with the surface of the tooth.