The majority of the time, brushing your teeth is sufficient to clean stained teeth, so they should go away as part of your regular oral hygiene and cleaning routine. Basic oral hygiene routines like brushing and flossing are quite effective. Yet, other factors in the mouth or even the body might occasionally cause discolored teeth. Dentists refer to stains on teeth as extrinsic when they are brought on by external factors; they refer to intrinsic stains as being brought on by internal factors.
Causes of Stained Teeth
Many factors can result in discolored teeth, including:
Bad dental hygiene
Failure to brush your teeth regularly will lead to tooth enamel decay and a variety of other problems, which may result in a variety of stains or tooth discoloration. Strive to make brushing your teeth every day a top priority.
Smoking tobacco
Cigarette smoke results in discolored teeth as well as a host of other harmful health problems. Nicotine stains can appear on both the front and back of the teeth. They are typically yellow stains with an orange tint.

Consuming Coffee
Coffee drinkers are well aware of how a morning cup of joe can perk you up, but they are also aware that it may leave behind brown stains. One of the most frequent causes of dental staining is coffee.
Tea drinking
Black teas are particularly problematic for leaving stains, and people are less aware of them than people are of coffee stains. Green tea or fruit can also discolor your teeth.
Red wine consumption
It can quickly leave your teeth with dark, reddish stains. Red wine and other alcoholic beverages stick to your teeth closely because of how closely they mimic the effects of sugar on teeth.
Older age
Teeth develop fully at a very young age, and as you age, tooth enamel naturally erodes. This can easily increase the visibility of stains. As you become older, yellow stains are typical.
Tooth Decay
The most fatal cause of discolored teeth is tooth decay. It causes dark and black stains on teeth. If your tooth decays, eventually deteriorates and may develop tooth pulp necrosis. Pulp Necrosis is a condition that can cause excessive pain.

Black Tartar
When bacteria build-up in your gum line it can cause dark, black stains on your teeth near the gum. Tartar is prone to spread to the whole mouth.
Infection Diseases
Infections in teeth rarely cause stains on teeth but it does. Treatments like cancers of the mouth or neck areas cause stained teeth like chemotherapy. The other cause of stained teeth is an injury, which causes discoloration in your tooth enamel.