Tooth decay occurs when so much of the mineral content of the tooth has been dissolved that a defect (hole) has developed in the tooth (Tooth). Tooth decay begins at the surface of the tooth, which is formed by tissues which have a high mineral content - enamel and dentin. Most of the exposed surface of a tooth is covered with enamel, which is over 95 percent mineral in composition. Most of the mineral in enamel is hydroxyapatite, which has a high calcium content. The bulk of the tooth is composed of dentin, which consists of about two thirds hydroxyapatite.
Tooth decay (cavities) first became pandemic in the 1700s with the establishment of sugar plantations, followed by the cultivation of sugar beet in Europe in the 1800s (Tooth). Tooth decay occurs by acid demineralization from acid created by certain bacteria. The bacteria responsible for creating cavities are Streptococci mutans and Lactobacilli, which consume sugars as food (glucose, sucrose, fructose, lactose, cooked starches) and produce acids as waste products. When a person eats, the bacteria immediately start eating the sugars and within minutes are producing the acid which causes tooth decay. Everyone's mouth contains millions of bacteria under normal conditions.
Dental plaque provides a place for bacteria to live, and also helps hold the acid they produce up against the surface of the tooth (Tooth). Acid produced by the bacteria can seep through the plaque down to the surface of the tooth, where it will not get washed away by saliva, which happens to acid on the exposed tooth surface. The older the plaque, the more effective it is at preventing the saliva from seeping in to neutralize the acid.
It takes several months or years for cavities to form in a tooth (Tooth). There has to be enough acid and enough dental plaque for demineralization to take place, which does not always happen. Also, remineralization of the tooth can take place using minera...