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Dental caries is a mouth disease that causes damage to certain structures of the tooth. This damage is caused by bacterial growth in the mouth. There are two types of bacteria that commonly cause this damage; a species called Streptococcus mutans, and species in the Lactobacillus genus. If not detected and treated, dental caries can lead to tooth decay, mouth infection and systemic infection that can, in rare cases, cause death. Dental caries is extremely common and can occur in people of any age.
Tooth decay, the common term for dental caries, occurs as a result of bacteria present in the mouth converting food into various types of acid. The easiest foods for bacteria to convert are sugars and starches, which is why these foods contribute most heavily to tooth decay. As bacteria process foods into acid, the acids, food debris and bacteria themselves combine to form plaque, a sticky substance that adheres to the teeth. If the plaque is not removed, it hardens over time and turns into tartar, which is not easily removed. At the same time, the acids produced by bacteria gradually dissolve tooth enamel, leading to cavities.
All of these processes combine to cause damage to tooth structures called enamel, dentin and cementum. Tooth enamel is the visible tissue of the tooth, a hard outer coating that is the hardest substance in the human body. Beneath the enamel layer, a layer of dentin provides support for the enamel. Cementum is a softer substance that covers the surface of the root of the tooth, below the gum line. As these tooth structures become progressively more damaged by food acids, plaque and tartar, the teeth decay and the gums become red, inflamed and susceptible to infection.
Once tooth enamel has been destroyed, it cannot regrow. To treat cavities, diseased portions of the tooth are removed and replaced with a nonbiological material such as amalgam, porcelain, resin or gold. In cases where there is too much decay to repair the tooth, it might be fitted with a cap called a crown, or it might be removed altogether.
The most effective treatment for dental caries is preventative treatment. Good oral hygiene, including regular brushing after meals and daily use of floss, reduces the amount of plaque on teeth and helps prevent the formation of tartar. Antiseptic mouthwashes also are useful to reduce the presence of bacteria in the mouth.
Dietary modifications can help reduce the risk of dental caries. The most significant modification is reducing the frequency of ingestion of sugary foods and drinks. In addition, avoiding snacking between meals helps prevent caries and tooth decay, because this reduces the supply of available food for bacteria, particularly if the teeth are brushed after each meal.
Very young children are at risk of early childhood caries if they are allowed to walk around or sleep with a bottle or cup of juice or milk, because if they have constant access to sugary liquids, their teeth are chronically exposed to sugars. This is a particular risk if they are given sugary drinks such as juices on a regular basis, but even milk and baby formula contain enough sugar to pose a risk. The risk of early childhood dental caries can be reduced by limiting juice to a meal-time drink only.