44+ Brown Stains On Teeth Causes. For permanent or stubborn brown spots on the teeth a dentist may be able to hide discolorations, or brown spots on the teeth are often the result of poor oral hygiene, smoking, or consuming many dark foods and drinks. The nicotine in tobacco causes brown and yellow stains on teeth, whether through smoking or chewing.
One of the most noticeable and unsightly stains on teeth are the brown stains.
The dark brown/black stains you see are extrinsic (meaning on the outside) stains. I brush twice a day, floss once a day, don't smoke, don't drink tea/coffee/anything that could stain my teeth, just. How does teeth whitening work? They may also represent superficial stains—like those produced by coffee, tea, wine, tobacco and food additives.