Tooth can become discolored by stains on the surface or by changes in the tooth material. Dentists divide discoloration into three main categories.
Extrinsic: This occurs when the outer layer of the tooth is stained.
Intrinsic: This is when the inner structure of the tooth darkens or gets a yellow tint.
Age-related: This is a combination of extrinsic and intrinsic factors. Dentin naturally yellows over time.
Yellow stains on the enamel. They can range from white streaks to yellow tints or brown spots and pits.