Cavities - tooth

Alternative names

Caries; Tooth decay; Dental cavities

Definition

Cavities are holes that damage the structure of teeth.

Causes, incidence, and risk factors

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 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 tartar. Plaque and tartar irritate the gums, resulting in gingivitis and ultimately periodontitis.

Plaque begins to accumulate on teeth within 20 minutes after eating (the time when most bacterial activity occurs). If this plaque is not removed thoroughly and routinely, tooth decay will not only begin, but flourish.

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 tooth and destroy the nerve and blood vessels in the tooth. If left untreated, a tooth abscess can develop. Untreated tooth decay also destroys the internal structures of the tooth (pulp) and ultimately causes the loss of the tooth.

Sugars and Starches increase the risk of tooth decay. 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.

Symptoms

• Toothache - particularly after sweet, hot, or cold foods and drinks
  
• Visible pits or holes in the teeth
  

Signs and tests
Most cavities are discovered in the early stages during routine checkups. The surface of the tooth may be soft when probed with a sharp instrument. Pain may not be present until the advanced stages of tooth decay. Dental x-rays may show some cavities before they are visible to the eye.

Treatment

Destroyed tooth structure does not regenerate. However, the progression of cavities can be stopped by treatment. The goal is to preserve the tooth and prevent complications.

In filling teeth, the decayed material is removed (by drilling) and replaced with a restorative material such as silver alloy, gold, porcelain, or composite resin. Porcelain and composite resin more closely match the natural tooth appearance, and may be preferred for front teeth. Many dentists consider silver amalgam (alloy) and gold as stronger and are often used on back teeth, although there is a trend to use high strength composite resin in the back teeth as well.