Many people wish to have bright white teeth and confident smiles, but teeth are often discoloured or stained due to different factors. Why are there stains? What should I do if I have teeth stains?
Teeth stains can be classified into extrinsic or intrinsic. Extrinsic stains are discolouration of the enamel on teeth surface, for example by tobacco products as well as dark foods and drinks such as tea and coffee. Intrinsic stains are discolouration within the teeth’s structure that may exist deep inside.
Extrinsic Teeth Stains
1. Food colouring / smoking
Frequent drinking of dark beverages such as tea and coffee will cause the enamel to absorb the colour of the food. The pigment will deposit on teeth surface and form teeth stains. When nicotine, tar and other substances in tobacco come into contact with oxygen, they will turn brown-yellow. They will firmly adhere to teeth surface and are difficult to be brushed away. Over time, the teeth will gradually become brown or even black. In addition to ultrasonic scaling, dentists can also clean teeth with sprayed powder. Making use of the air, fine soda powder (Sodium Bicarbonate) mixed with water is sprayed at high speed with a nozzle on teeth surface to remove stubborn teeth stains
(Image source: Google) 
2. Accumulation of plaque and tartar
Plaque accumulated on teeth surface contains colour-emitting bacteria which will form orange stains. Poor oral hygiene can lead to tooth decay, with accumulated plaque eroding the enamel and producing white spot lesions. Proper brushing and flossing can prevent the accumulation of dental plaque and tartar. Dentists will clean the teeth with ultrasonic equipment to remove stubborn tartar and pigment.
(Image source: Google) 
Intrinsic Teeth Stains
1. Necrosis of dental nerves
Impacted teeth or severe tooth decay can lead to the necrosis of nerves. Substances released from the necrotic pulp will penetrate into the dentin, making the teeth brown or gray. Teeth discolouration caused by pulp necrosis requires root canal therapy. If the teeth still appear gray or black after such therapy, bleaching, veneers or crowns can be applied to change the colour of the teeth.
(Image source: Google)
2. Side effects of drugs or treatments
The use of certain drugs during pregnancy and infancy may cause teeth stains, such as tetracycline. Young children or pregnant women taking this antibiotic will cause the children’s permanent teeth to become blue-green. Bleaching, veneers or crowns can be applied to change the colour of the teeth.
(Image source: Google)
3. Infection during teeth development
If the pulps of deciduous teeth are infected due to severe tooth decay, the infected deciduous teeth roots will affect adjacent permanent teeth which are under development, causing the enamel of the permanent teeth to turn brown-yellow or have white spots. Bleaching, veneers or crowns can be applied to change the colour of the teeth.
(Image source: Google)
4. Mineral imbalance
Insufficient fluoride in drinking water or the excessive intake of fluorine will cause white or brown spots on teeth surface. This kind of discolouration exists inside the teeth structure, so ceramic fillings, veneers or crowns are required to change the colour of the teeth.
(Image source: Google)
Tips to prevent teeth stains
~ Brush and floss properly
~ Avoid staining foods and drinks
~ Reduce or quit smoking
