Enamel is the hard translucent outer layer of teeth, dentin is the softer layer which is located under the enamel. Below the dentin is the pulp chamber filled with nerves and blood vessels, this is considered the vital part of the tooth. Caries is the progressive destruction of a tooth caused by acid. This acid is produced by bacteria contained within dental plaque. Caries passes through several stages of development.
Bacteria on the surface of the tooth use sugars to create the ideal conditions for the formation of caries by forming acids and lowering the pH. If there is no change in the pH level for a long period of time it will cause significant loss of mineral content in the enamel. This is the development of the initial caries lesions which leave a chalky–white color stain. At this stage the process of tooth decay can be prevented by establishing good oral hygiene and removing the plaque with the use of fluorides.
As the process continues, demineralization of the enamel continues as well. Once the enamel surface on a tooth is eroded, the tooth cannot be healed. The dentist has to remove the carious mass from the cavity and reconstruct the tooth.
If left unchecked the process will continue and the caries will penetrate into the dentin, where it will spread and undermine the remaining enamel.
Eventually untreated caries will reach the pulp and the pulp will becomes infected. If this occurs an infection of the root canal is not far behind. From there is can lead to more serious health issues.
A regular dental appointment and good oral hygiene will help prevent tooth decay.