In the area of a situation crown covers the tooth enamel. It is the strongest tissue in the body, before the mandible - the toughest of all bones. The melting consists of 98 percent from the mineral salts of calcium, phosphate and fluoride. The fluorine compounds are for the extraordinary hardness of this tissue is responsible. Healthy tooth enamel is nearly every mechanical strain grown, but not all chemical and biological substances: acids and bacteria can also be the most stable enamel to cauterize and sodden.