Tooth Decay (Dental Caries) (Dental Cavities)
Tooth decay, technically known as dental caries is an infectious process which damages the structures of teeth. Strictly speaking, “dental caries” means holes in the outer two layers of the teeth, the enamel and the dentin. Theoretically, one could use a drill to produce “dental caries.” The usual cause of caries is the dissolution of these two layers by acid produced by bacteria which have grown on the surface of the tooth. Tooth decay, or “cavities,” are the consequence of caries. If left untreated the disease leads to pain and loss of teeth, as well as infection and, in severe cases, death through the spread of the infection of other organs. Tooth decay was present in the Bronze, Iron, and Medieval ages but also even prior to the neolithic period, however the enormous increase in the prevalence of caries is associated with the various modern diets. The so-called “paleolithic diet” produced very few cavities.
Tooth decay is caused by acid-producing bacteria which cause damage by metabolizing fermentable carbohydrates such as sucrose, fructose, and glucose. The resulting acidic levels in the mouth affects teeth because a tooth’s special mineral content causes it to be sensitive to acid. Teeth are in a constant state of mineralization and demineralization and when the pH (a measure of acidity and alkalinity) at the surface of the tooth drops below 5.5 (very acid), demineralization proceeds faster than remineralization and there is a net loss of mineral structure and this defines “decay.” Various treatments are used to restore teeth to proper form, function, and to restore their appearance, but there is no known method to regenerate large amounts of tooth structure. Instead, dental health organizations advocate preventive and prophylactic measures such as regular flossing and brushing and also dietary modifications to avoid simple sugars.
An untreated caries may appear as a small chalky area at first, but eventually develops into a large, brown cavitation. Although sometimes caries may be seen directly, x-ray examinations are often needed to discover less visible areas of teeth and to judge the extent of destruction.
Ninety percent of schoolchildren worldwide and most adults have experienced tooth decay with the disease being most common in Asian and Latin American countries and least prevalent in African countries. In the U.S. tooth decay is the most common chronic childhood disease, five times more common than the runner up, asthma. It is the primary pathological cause of tooth loss in children and many adults over the age of 50 experience tooth decay. After 50 gum recession away from the tooth exposes more and more of the dentin which is below the gum line in younger people. Dentin is less resistant to caries than enamel.
The number of cases has decreased in some developed countries, and this decline is attributable to better oral hygiene practices. However, there is still a disparity in the distribution of the disease. Among children in the U.S. and Europe, 70% of cases of tooth decay occur in 20% of the population. A similarly skewed distribution of the disease is found throughout the world with some children having none or very few caries and others having a high number. There is surely a socio-economic influence as well as a genetic influence, not to mention the dietary influence.
The subject of the addition of fluoride to prevent cavities, its effect on general health and its association with cancer is dealt with elsewhere.