Why are teeth white? One Hundred Thousand Whys

The surface of the crown with normal tooth color is covered with a layer of enamel, which is medically called enamel. The normal thickness is about 2-2.5 mm, and the dentin below is yellow or light yellow. Generally speaking, the higher the degree of calcification, the more transparent the enamel is, and the yellow below it is easier to penetrate and develop color, so the normal and healthy crown is generally yellowish and translucent ivory color. Early childhood deciduous teeth have low calcification and low transparency, showing milky white, which is whiter than the replaced permanent teeth. Even with the same permanent tooth, the color of the tooth gradually turns yellow with the increase of age, so the teeth of young people are whiter than those of the elderly. The causes of abnormal tooth color are exogenous and endogenous. The former can be due to frequent consumption of food or drugs containing pigments, such as tea, coffee, Chinese medicine and so on. And the pigment is deposited on the tooth surface, or because of frequent smoking, the smoke spots cover up the original tooth color and are dull. Endogenous coloring is influenced by drugs, trace elements or general conditions during tooth development, such as tetracycline teeth and dental fluorosis. If your front teeth are obviously gray and black, you can recall whether you have had bumps or injuries. In addition, the teeth with nerve treatment will also change the color of teeth because of the change of blood supply.