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The enamel on primary teeth has a more opaque crystalline form and thus appears whiter than on permanent teeth. The large amount of mineral in enamel accounts not only for its strength but also for its brittleness. [6] Tooth enamel ranks 5 on Mohs hardness scale (between steel and titanium) and has a Young's modulus of 83 GPa. [4]
Dissolved minerals then diffuse out of the tooth structure and into the saliva surrounding the tooth. The buffering capacity of saliva greatly impacts the pH of plaque surrounding the enamel, thereby inhibiting caries progression. Plaque thickness and the number of bacteria present determine the effectiveness of salivary buffers. [4]
Acid erosion is a type of tooth wear.It is defined as the irreversible loss of tooth structure due to chemical dissolution by acids not of bacterial origin. [1] Dental erosion is the most common chronic condition of children ages 5–17, [2] although it is only relatively recently that it has been recognised as a dental health problem. [3]
In most people, disorders or diseases affecting teeth are not the primary cause of dental caries. Approximately 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]
Hydroxyapatite is present in bones and teeth; bone is made primarily of HA crystals interspersed in a collagen matrix—65 to 70% of the mass of bone is HA. Similarly HA is 70 to 80% of the mass of dentin and enamel in teeth. In enamel, the matrix for HA is formed by amelogenins and enamelins instead of collagen. [17]
Topical fluorides are fluoride-containing drugs indicated in prevention and treatment of dental caries, particularly in children's primary dentitions. [1] The dental-protecting property of topical fluoride can be attributed to multiple mechanisms of action, including the promotion of remineralization of decalcified enamel, the inhibition of the cariogenic microbial metabolism in dental plaque ...
Saliva gradually neutralises the acids, which causes the pH of the tooth surface to rise above the critical pH, typically considered to be 5.5. This causes remineralisation, the return of the dissolved minerals to the enamel. If there is sufficient time between the intake of foods then the impact is limited and the teeth can repair themselves.
Amine fluorides have a slightly acidic pH. For this reason, fluoride ions can combine rapidly with the calcium in dental enamel to form calcium fluoride. This acts as a fluoride depot over a longer period: Under cariogenic conditions fluoride ions are made available stimulating the remineralisation of dental enamel and thus prevent acid attacks.