There are certain dental diseases and disorders that may increase an individual’s risk of caries.
Hypomineralization of the molar incisors appears to be increasingly common.[35] While the cause is unknown, it is believed to be a combination of genetic and environmental factors.[36] Possible contributing factors investigated include systemic factors such as high levels of dioxin or polychlorinated biphenyls (PCB) in breast milk, premature birth and oxygen deprivation at birth, and specific disorders during the first 3 years of life such as mumps, diphtheria, and scarlet fever , measles, hypothyroidism, malnutrition, malabsorption of blood, vitamin D deficiency, chronic respiratory disease, or undiagnosed and untreated celiac disease, which usually presents with or is absent gastrointestinal symptoms.[35][37][38] [39][40][41]
Hyaluronic acidemia, which occurs between 1 in 718 and 1 in 14,000 individuals, is a disease in which the enamel does not form fully or insufficiently and can fall off the teeth.[42] In either case, the tooth may be left more vulnerable to decay because the enamel is unable to protect the tooth.[43]
In most people, dental disorders or diseases are not the main cause of tooth decay. About 96% of tooth enamel is composed of minerals.[44] These minerals, especially hydroxyapatite, will become soluble when exposed to acidic environments. Enamel begins to demineralize at a pH of 5.5.[45] Dentine and cement are more susceptible to decay than enamel because they contain less minerals.[46] Thus, when the root surfaces of the teeth are exposed to gingival recession or periodontal disease, caries can develop more easily. Even in a healthy oral environment, the tooth is vulnerable to tooth decay.
Evidence linking malocclusion and/or crowding to caries;[47][48] however, dental anatomy may influence the potential for caries formation. When the grooves of deep developmental teeth are more numerous and exaggerated, pit and fissure caries are more likely to develop (see next section). Also, cavities are more likely to develop when food gets trapped between the teeth.
