![]() Dentin, less mineralized and less brittle, 3–4 in hardness, compensates for enamel and is necessary as a support. Tooth enamel ranks 5 on Mohs hardness scale (between steel and titanium) and has a Young's modulus of 83 GPa. The large amount of mineral in enamel accounts not only for its strength but also for its brittleness. The enamel on primary teeth has a more opaque crystalline form and thus appears whiter than on permanent teeth. Since enamel is semitranslucent, the color of dentin and any material underneath the enamel strongly affects the appearance of a tooth. At the edges of teeth where there is no dentin underlying the enamel, the color sometimes has a slightly blue or translucent off-white tone, easily observable on the upper incisors. The translucency may be attributable to variations in the degree of calcification and homogeneity of the enamel. It has been suggested that the color is determined by differences in the translucency of enamel, yellowish teeth having a thin, translucent enamel through which the yellow color of the dentin is visible and grayish teeth having a more opaque enamel. The normal color of enamel varies from light yellow to grayish (bluish) white. ![]() In humans, enamel varies in thickness over the surface of the tooth, often thickest at the cusp, up to 2.5 mm, and thinnest at its border with the cementum at the cementoenamel junction (CEJ). The maintenance and repair of human tooth enamel is one of the primary concerns of dentistry. Remineralisation of teeth can repair damage to the tooth to a certain degree but damage beyond that cannot be repaired by the body. Once fully formed, enamel does not contain blood vessels or nerves, and is not made of cells. Enamel is formed on the tooth while the tooth develops within the jaw bone before it erupts into the mouth. The primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. ![]() Features Įnamel is the hardest substance in the human body and contains the highest percentage of minerals (at 96%), with water and organic material composing the rest. In rare circumstances enamel fails to form, leaving the underlying dentin exposed on the surface. It is a very hard, white to off-white, highly mineralised substance that acts as a barrier to protect the tooth but can become susceptible to degradation, especially by acids from food and drink. The other major tissues are dentin, cementum, and dental pulp. It makes up the normally visible part of the tooth, covering the crown. Tooth enamel is one of the four major tissues that make up the tooth in humans and many animals, including some species of fish. Parts of a tooth, including the enamel (cross section).
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