The color or shade of teeth is effected by two primary factors. The intrinsic shade is the natural shade of the tooth determined by the coloring of the surface enamel and internal dentin laid down as the tooth was forming in the jaw bone. The natural coloring of teeth generally corresponds to hair, eye and skin color, but tends to darken with age and loss of vitality. This is why root canal treated teeth are often darker than their neighbors.
The second factor in the perceived color of a tooth is surface staining. When bacterial plaque remains on a tooth, the plaque can acquire coloration from dietary components such as red wine, coffee and tea. Smoking can also contribute to surface staining, making teeth appear darker.
There are different ways to lighten teeth, depending upon the nature of the darkened color. Sometimes thorough scaling and polishing by good home care will suffice to allow the natural color of the teeth to be seen. If the teeth are naturally too dark, they can be lightened by using tooth whitening (bleaching), veneers or crowns.