Dental caries is an infectious disease which damages the structures of teeth .. blank">Dental Cavities, MedlinePlus Medical Encyclopedia, page accessed August 14, 2006. Tooth decay or cavities are consequences of caries. If left untreated, the disease can lead to pain, tooth loss, infection, and, in severe cases, death of the tooth. There is a long history of dental caries, with evidence showing the disease was present in the _Bronze, Iron, and Medieval ages but also prior to the neolithic period. 1Epidemiology.htm" target="_blank">Epidemiology of Dental Disease, hosted on the University of Illinois at Chicago website. Page accessed January 9, 2007. The largest increases in the prevalence of caries have been associated with diet changes. Epidemiology of Dental Disease, hosted on the University of Illinois at Chicago website. Page accessed January 9, 2007. Suddick, Richard P. and Norman O. Harris. "Historical Perspectives of Oral Biology: A Series". Critical Reviews in Oral Biology and Medicine, 1(2), pages 135-151, 1990. Today, it remains one of the most common diseases throughout the world.

There are numerous ways to classify dental caries. Sonis, Stephen T. "Dental Secrets: Questions and Answers Reveal the Secrets to the Principles and Practice of Dentistry." 3rd edition. Hanley & Belfus, Inc., 2003, p. 130. ISBN 1-56053-573-3. Although the presentation may differ, the risk factors and development among distinct types of caries remain largely similar. Initially, it may appear as a small chalky area but eventually develop into a large, brown cavitation. Though sometimes caries may be seen directly, radiographs are frequently needed to inspect less visible areas of teeth and to judge the extent of destruction.

Tooth decay is caused by certain types of acid-producing bacteria (specifically _Lactobacillus and Streptococcus mutans) which cause damage in the presence of fermentable carbohydrates such as sucrose, fructose, and glucose. Hardie, J.M. (1982). The microbiology of dental caries. Dental Update, 9, 199-208. Holloway, P.J. (1983). The role of sugar in the etiology of dental caries. Journal of Dentistry, 11, 189-213. The resulting high levels of acidity from lactic acid in the mouth affect teeth because a tooth's special mineral content causes it to be sensitive to low pH. Specifically, a tooth (which is primarily mineral in content) is in a constant state of back-and-forth demineralization and remineralization between the tooth and surrounding saliva. When the pH at the surface of the tooth drops below 5.5, demineralization proceeds faster than remineralization (i.e. there is a net loss of mineral structure on the tooth's surface). This results in the ensuing decay. Depending on the extent of tooth destruction, various treatments can be used to restore teeth to proper form, function, and aesthetics, 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 oral hygiene and dietary modifications, to avoid dental caries. Oral Health Topics: Cleaning your teeth and gums. Hosted on the American Dental Association website. Page accessed August 15, 2006.