Yellow Teeth: Common Causes to Tooth Staining and Discolouration

At Highgate Hill Dental Centre, we often see people who are concerned about the yellow colour of their teeth or the appearance of new marks and stains. This is a perfectly normal concern. Teeth can display a wide range of colours depending on both their internal and external environment. The outward appearance of a tooth tells the story of both current and past environments. Sometimes a dark spot on a tooth can be just that, but sometimes it can indicate something going on beneath the surface.

Causes of Staining:

The causes of tooth discolouration can be broken down into three categories – intrinsic, extrinsic, and age-related. Intrinsic causes are those that result in staining or discolouration below the surface of the tooth. Extrinsic discolouration is that on the enamel of the tooth. As would be expected, age-related colour changes are a combination of intrinsic and extrinsic factors that become apparent as we get older.

1. Extrinsic:

Some of the most common culprits of external staining are food and drink that have strong pigments. Due to the porous nature of enamel, prolonged or frequent exposure to strongly coloured substances can lead to the uptake of these colours. The combination of food acids and bright colours creates an environment in which colours can adhere to the tooth surface and cause discolouration.

Think of it as washing a white t-shirt amongst coloured ones – eventually that white t-shirt will lose its brightness and begin to take on the colours of its surroundings.

Many of our favourite beverages can also cause staining due to their high levels of tannins, or tannic acid.

Some common examples of stain-causing food and drink are:

  • Coffee
  • Red wine
  • Blueberries
  • Tea
  • Curries
  • Carbonated drinks

Take a look at the image below – the effect of coffee on a white cup is similar to that on our teeth.

As well as our diet, other lifestyle factors can contribute to tooth discolouration. Tar and nicotine present in cigarettes can cause teeth to yellow and accumulate plaque at a faster rate. Heavy and frequent exposure to the toxic contents of cigarettes can result in the teeth taking on various shades of brown.

Surprisingly, something as simple as swimming in a chlorinated pool can lead to changes in tooth colour. The altered pH balance of chlorinated pools can result in a condition known as ‘swimmers calculus’. Chlorinated water changes molecules in saliva, leaving behind hard, brown tartar deposits. This is often seen in people who spend a lot of time in the water, especially children.

Some chlorhexidine containing mouthwashes can also cause staining if used for prolonged periods of time.

2. Intrinsic:

Intrinsic discolouration predominantly affects the inner layer, or dentin of the tooth. Common causes of intrinsic staining include:

  • Too much fluoride
  • Use of tetracycline antibiotics
  • Direct trauma to the teeth
  • Genetic conditions such as dentinogenesis imperfecta

3. Age-related:

As we get older, our teeth naturally yellow. This is due to a number of processes that occur throughout the lifespan.

  • Dentin (inner layer of the tooth) becomes thicker and more yellow.
  • Thinning of the enamel allows the yellow dentin to show through.
  • Gum recession results in exposure of the root surface of the tooth which has a more yellow appearance than the enamel.


Dr Kathleen Ling suggests these simple things to safeguard your teeth against staining or discolouration.

  • Rinsing your mouth out with water after food or drink that is particularly colourful or acidic.
  • Drinking acidic or carbonated beverages through a straw.
  • Regular brushing and flossing.
  • Wear a mouthguard when participating in contact sports.
  • Stick to the guidelines when it comes to fluoride requirements for children.


The treatment of tooth discolouration or staining is largely dependent on the cause. Most marks on the outside of teeth cannot be removed by brushing alone as they are embedded in the enamel. Sometimes a simple professional scale and clean at the dentist can clean the stains off, however sometimes it requires a bit more. Your dentist will be able to tell you more about your individual situation and the best way forward to a happy, healthy smile. If you are concerned about staining or discolouration of your pearly whites, come and have a chat at your next check-up.