1, physiological changes in tooth color: human teeth with age and long-term use, will gradually have a slight change in color.
2, exogenous yellow teeth: Because the food pigment affixed to the tooth surface, is yellow or gray, smoking smoke scale, drink, coffee, tea pigment and other adhesion teeth are yellow gray.
3, Endogenous yellow teeth: the tooth is affected by some element, the pigment is not on the tooth surface and in the tooth tissue, there are two main types: dental fluorosis and tetracycline teeth.
4. The tooth itself is yellowish: this condition is related to heredity and tooth development.
5, there are individual teeth due to dental pulp necrosis, teeth lack of nutrition caused by the crown discoloration.