What dictates teeth color?
There are a few factors: the thickness and brightness of the enamel (outer layer of the tooth), and the dentin (nerve) underneath it, which is naturally yellowish. So people with the genes for thick enamel and lighter dentin will have whiter teeth. However, this color can change due to factors such as staining on the enamel from certain foods. Whitening products and dental hygiene aim to eliminate staining and return teeth to their former shade.