Enamel protection
Demineralization and remineralization
Tooth enamel is constantly undergoing a process of demineralization and natural remineralization in the saliva enhanced by the presence of fluoride. Click here to view an animation about this process.
Dental enamel consists of densely packed mineral crystals (mainly hydroxyapatite) and it can become demineralized due to exposure to plaque acids. Plaque formation is promoted by eating sugary foods and/or poor tooth brushing technique. In the early stages of demineralization, the tooth surface remains intact and demineralization is reversible. However, once it reaches a certain level, the tooth surface collapses exposing a cavity. [Arends et al, 1984]
Fluoride is a natural element found in the earth's crust as well as in water. A link between fluoride and fewer tooth cavities was first shown in the early 1930s. At this time, dentists observed that people living in regions of the USA where the water contained naturally high levels of fluoride typically had teeth with low levels of decay.
Fluoride ions adsorb to the surface of the enamel, and can protect that surface against acid attack. Fluoride absorption in carious enamel is increased as compared with sound enamel due to the increased porosity and increased surface area of the demineralized regions.
Fluoride ions can penetrate below the surface of carious enamel and stimulate the remineralization of the enamel by encouraging the precipitation of minerals incorporating fluoride (fluoridated apatite and calcium fluoride). These are more resistant to acid attack than their unfluoridated forms due to the formation of less soluble fluoride-containing lattices, thereby slowing or halting the progress of caries development. [Arends et al, 1984; ten Cate, 1999]
To view animations depicting these processes click here and here.
