Pathogenesis Dental caries begins on the external crown or exposed root surface of the tooth. Bacterial plaque, not food debris, causes caries. Plaque is not flushed away by the action of oral musculature or saliva. The role of saliva in preventing caries is in its buffering capacity, remineralization effect, and secretory immunoglobulines. When the carious process reaches the dentin or begins on the roof surface, the tooth becomes sensitive to temperature or osmotic changes engendered by foods or by touch.
Caries spreads rapidly because of the lower mineral content of dentin and cementum.
The patient is often unaware of the presence of caries until the lesion is well advanced. Common early symptoms are sensitivity to heat and cold and discomfort after eating sugar-containing foods. There is no proof that ingesting fluoridated water or fluoride supplements during pregnancy will significantly protect a child's deciduous teeth and permanent 1st molars. Ingesting excessive fluoride before eruption, while the enamel is forming, may cause permanent mottling of the enamel. Once erupted, teeth cannot develop mottling when exposed to excessive fluoride.