You have tooth discoloration when your teeth are stained or darkened. It might affect the whole tooth or look like lines or spots on the tooth’s surface. There are two basic types of tooth discoloration:

1. Intrinsic or Internal Discoloration happens inside the tooth. Things that can cause this type of discoloration include aging, tooth injuries, some health conditions, and certain medications.
2. Extrinsic or External Discoloration happens when substances like foods, beverages, or tobacco stain the tooth’s surface. Poor oral hygiene can also cause it.

Tooth whitening cannot make a complete color change, but it may lighten the existing shade and is not permanent.

Currently, bleaching agents which are used are based primarily on either hydrogen peroxide or carbamide peroxide. The peroxide oxidizing agent penetrates the porosities in the rod-like crystal structure of enamel and breaks down the stain.

Yellowish teeth respond well to bleaching compared to brownish-colored teeth. Gray/purple or tetracycline stains are more difficult to light and may require prolonged bleaching. The effect is less likely to last as long if you smoke, eat or drink products that stain your teeth.