The Teeth Color:
The teeth color is determined by multiple factors among which are genetic, age, food.
For this we only have to take a look at the anatomy of a tooth, the structure that occupies more volume on a tooth is the dentin, which has a yellowish-brown color, while the enamel, which occupies a smaller volume being a external thin layer of the tooth is by transparent. The smaller volume of enamel the greater enamel color perception of the dentin.
In terms of age, over the years, the enamel wears by making it even more translucent and allowing see more color of dentin, so the appearance of teeth are more yellow-brown.
Drugs and diseases can also determine the color of the teeth, enamel hypoplasia or genetic disease that causes deformity of the dental enamel. Also the use of tetracyclines may cause defects in enamel formation in children when the permanent tooth is yet to erupt.
Food: Certain high acid foods can wear down the enamel so fast such as citrus. Beverages and food colorants may be pigmented with the teeth of the same color changing over time, for example wine. Excess fluoride in water also causes white spots on teeth.
To conclude, we can say that there are teeth color vary and in most cases they are not related to any disease, and its not true that people of different races have a more white on your teeth than others.
We refferences: Dentin Hypoplasia – Brooklin Hospital Center