What Stains Teeth and Teeth Discoloration

Teeth can discolor over time due to a variety of factors.  Teeth can also become discolored as they develop in the jaws.  This article will give you advice on what stains teeth, as well as what can cause the them to discolor when they are developing.

There are two main types of discoloring that affect teeth; stains on the outer surfaces (so the color of the tooth is unchanged) and discoloring of the tooth (i.e. the inner part of the tooth) itself.  Let’s look at these in more detail:

Image of stained lower teeth

Crowded teeth like this can be harder to clean, with resulting tooth stains

1. Outer or ‘extrinsic’ discoloration.  This is simply stains on the visible outer surface.  The actual underlying color of the tooth is unaffected.


What stains teeth?  Some of the common examples of what stains teeth are:

  • Coffee; especially black coffee.  Coffee stains more than tea does.
  • Tea; again, especially when black.
  • Red wine.
  • Dark cola drinks and some fruit juices (cranberry and grape for example).
  • Certain foods such as curries and dark berries.
  • Smoking (and chewing) tobacco.
  • Chlorhexidine mouthwash; a common example of what stains teeth, but one that you may not be aware of!
  • Poor oral hygiene can result in green or black staining.
  • Iron supplements and some medications.


2.  Inner or ‘Intrinsic’ discoloration.  Here it is the actual tooth substance (mainly the dentin) that changes the outer color.  There are many causes:

  • Age.  Teeth discolor naturally with age as the (darker) dentin thickens and the enamel thins.
  • Tetracycline.  This is a type of antibiotic.  If taken when the dentition is forming it can make the them characteristically dark (sometimes severely so).  The type of discoloring is often evident on the teeth as ‘banding’; horizontal bands of different shades are present.  People with tetracycline staining were exposed to the drug when still in the womb or when at a young age.
  • Genetic causes.  Some rare conditions can cause tooth discoloration.
  • Nerve damage.  If the nerve inside a tooth dies, from decay or the tooth getting a knock (trauma), the dead tooth can darken (see image).  This is the most common cause of a single (or a few) tooth becoming discolored on their own.
    "Image of teeth that are dark due to trauma and need root canal"

    The dark shade here is internal discoloration and indicates nerve damage

  • Fluoridosis.  Exposure to too much fluoride when the dentition are developing can cause them to form discolored.


“What Type of Stains do I Have?”

Outer stains on teeth can be identified as discoloring that worsens over time and between professional dental cleanings.  Staining tends to be worse in areas that are hard to clean, for example:

  • In between teeth.
  • At the edges around some types of filling.
  • On those that aren’t straight, e.g. a tooth that lies slightly behind the others.

Some people have teeth which tend to collect staining easily.  This may be due to microscopic roughness, pitting and cracking of the enamel surface.

Intrinsic discoloring is characterized as usually being present from the time of eruption (exceptions are nerve damage and age-related discoloring) and cleanings etc. will not help change the color.


Prevention of Teeth Stains

While staining and discoloration is a common problem, there are steps you can take to prevent it.

Here are useful tips for preventing stains from building-up:

  • Cut down on what is causing the staining (listed above).
  • Brush twice daily.  Do not brush immediately after a meal, however, as this can weaken the teeth over time.  Instead rinse out with a mouthwash or water after a meal/drink.
  • Some whitening toothpastes may help.  Whitening toothpastes contain more ‘abrasives’ that help increase their ability to remove stains.
  • Change your toothbrush every three months.
  • Clean between the teeth with floss or inter-dental brushes.


If you have intrinsic discoloring, the damage has been done, i.e. it is too late for ‘prevention’.  Preventing intrinsic discoloration from occurring in the first place includes:

  • Tetracycline should not be taken by pregnant women or children under 8 years of age.
  • Fluoride supplements should be taken in recommended doses.
  • Teeth that have nerve damage are less likely to darken if the root canal treatment is carried out sooner rather than later.


Treatment of Discolored Teeth

Treatment will vary depending on the extent and type of discoloring:

Some tooth discoloration can be removed with professional cleaning. An example would be the stains caused by coffee.  Many stains are permanent, however.  Teeth sometimes can be whitened with a bleaching gel.  In some cases, if the discoloration is severe, a crown or veneer may be required to cover it.


Outer staining:


‘Whitening’ toothpaste will not change the color of your teeth, but can help reduce staining. Be careful of overly abrasive pastes

Regular professional dental cleanings will remove most outer staining.  Whitening toothpastes may be useful in removing stains, but these will not change the underlying shade of your teeth.


Intrinsic discoloration:

When it is the actual color of the teeth and not outer staining that is the problem, there are several treatment options.

  • Professional tooth whitening.  This may involve ‘power’ bleaching at the dentist and several repeat treatments may be needed to get a satisfactory result.  Alternatively, or in combination with this, the dentist may prescribe an ‘at-home’ whitening kit for use over several weeks.
  • Over-the-counter whitening products.  e.g. whitening strips.

In the case of severe discoloration or when the teeth are also broken down or heavily filled, whitening may not be a satisfactory treatment.  Tetracycline-affected dentitions characteristically are difficult to whiten.  They may change shade with intensive whitening treatments but ‘banding’ (i.e. variations of shade within each tooth) will persist.

Where whitening is not suitable, restorative dental work such as veneers and crowns may be the best choice of treatment.

In the case of one or more ‘dead’ teeth being discolored through nerve damage, a type of whitening treatment can be applied to the inside of the tooth.   Alternatively, if the tooth is damaged or weak, a crown may be necessary.



There are many everyday examples of what stains teeth.  Outer staining is different to inner discoloration.  It is important to know what type of discoloration you may have, as any treatment may be different for different types of discoloration.

Outer staining can be cleaned by your dentist and prevented by avoiding certain foods and products that stain the teeth.  One common treatment for inner stains is professional teeth whitening.

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