Dental caries occurs due to demineralization of enamel and dentine (the hard tissues of the teeth) by organic acids formed by bacteria in dental plaque through the anaerobic metabolism of sugars derived from the diet. The 2 primary bacteria involved in caries formation are mutans streptococci and lactobacilli. When sugars or other fermentable carbohydrates are ingested, the resulting fall in dental plaque pH caused by organic acids increases the solubility of calcium hydroxyapatite in the dental hard tissues and demineralization occurs as calcium is lost from the tooth surface. The pH at which demineralization occurs is often referred to as the critical pH and is approximately 5.5.
