Why do our teeth go yellow?

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While celebrities often have perfect pearly whites, most of our smiles are a little duller. But why?

The main cause of our teeth going yellow is lifestyle. Smoking, drinking coffee and tea, and chewing tobacco are the worst offenders. The tar and nicotine in tobacco are chemicals that lead to yellow stains on the surface of the teeth. As a general rule, any food or drink that can stain your clothes can have the same effect on your teeth. This is why dark coloured food and drinks, such as red wine, chocolate and dark sauces like soya sauce and balsamic vinegar, can also discolour your teeth,

Note also that certain fruit and vegetables – such as grapes, blueberries, cherries, beetroot and pomegranates – can stain the teeth. These foods are rich in chromogenic bacteria, which produce pigments that can stick to the teeth’s enamel. Lollipops and sweets are other products that have similar consequences. Addionally, acidic food and drink promotes the appearance of stains by eroding the teeth’s enamel and causing the pigments to set. Tannin, a bitter compound present in wine and tea, also helps the chromogenic bacteria to attach to the enamel. In order to prevent “external” staining, effective and regular brushing is naturally essential.

There are also stains referred to as “intrinsic” stains, which are produced in the internal dentine of the tooth, and which are more difficult to remove. Numerous medications can cause intrinsic stains, such as tetracycline or doxycycline antibiotics. In adulthood, the use of a prescription mouthwash containing chlorhexidine, a compound that reduces bacteria and treats gingivitis (inflammation of the gums), can cause brown discolouration on the teeth. Additionally, minocycline, an acne treatment derived from tetracycline, also discolours the teeth, as do certain relatively common medications, such as antihistamines, antipsychotics and blood pressure medication.

Note that chemotherapy and radiotherapy targeted at the head and neck can lead to the appearance of intrinsic stains. Genetics can also play a role: dentinogenesis and amelogenesis are two hereditary conditions that lead to poor development of the teeth and which can lead to discoloration. Heredity is also why certain people have a whiter or thicker enamel than others. You can simply be born with teeth that appear yellower (or whiter) by comparison to others. If you have a fine layer of enamel, the real colour of your dentine (which is naturally yellowish) will be more visible.

Age also darkens the colour of your teeth: as you get older, the outer layer of enamel gets thinner, making the teeth appear yellower. Their colour can also be affected by illness. Yellowing often occurs after having suffered a high fever at a young age, due to an infection. Finally, falls or sports injuries in young children can disrupt the formation of the enamel while children’s permanent teeth are still developing.

In short, the causes are numerous. The best prevention method is to watch what you eat and drink (and try not to smoke). It is also recommended that you maintain good dental hygiene and consult a dental professional at least twice a year.


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