Normal teeth consist of enamel, dentin and cementum. Enamel is a colorless and transparent hard tooth tissue layer on the tooth surface. Dentin is the main component of teeth, located in the inner layer of enamel and cementum, and is also the side wall of pulp cavity and root canal. The color is yellow, and the edges of teeth are mostly enamel, so the color is transparent. Yellowing of teeth is mainly caused by the color of internal dentin leaking to the surface of teeth.
Therefore, the color of teeth is the color of dentin, and yellowing of teeth is normal. If you feel yellow, you can improve it by cold light whitening.