Colour of the teeth

internal teeth stain

Since the enamel of permanent teeth is slightly transparent, the yellowish colour of the underlying dentine is shown through it.  Therefore, permanent teeth will appear slightly yellowish.  As we get older, the dentine increasingly grows thicker, and it is normal that our teeth become more yellowish.

Translucent yellow adult teeth

The enamel of deciduous teeth is not as transparent as our permanent teeth.  That is why deciduous teeth look milky white

Milky white deciduous teeth

Factors causing tooth discoloration

There are two factors causing tooth discoloration — internal factor and external factor.

A. External factors causing tooth discoloration

  1. Brown and black stains on the surface of teeth

Teeth with black stains

Cause: Drinking of dark-coloured beverages, such as tea, coffee result in the food colours being adsorbed onto the tooth surfaces

Treatment: Dentist would use dental pumice to remove the stain, and then prophylaxis paste to smoothen the tooth surfaces and or scaling and polishing

Prevention: Avoid drinking dark-coloured beverages to minimize food colours being adsorbed.

Green and orange stains at the surface of teeth 

Teeth with orange stain

Teeth with green stain

Cause: Teeth has not been cleaned thoroughly, and the accumulated dental plaque contained bacteria or fungi that can produce colour and formed green and orange stains.

Treatment: Dentist will perform scaling to remove accumulated dental plaque and stains.

Prevention: Brush the teeth every morning and before bed at night, and use dental floss to remove dental plaque to keep the teeth white.

  • B. Internal factors causing tooth discoloration

  • Teeth appear to be greyish-blue to brownish-yellow

If there was certain sickness or, if tetracycline (a kind of antibiotics) is taken during the development of teeth, the teeth formed will be greyish-blue to brownish-yellow.
Cause: If there was certain sickness or, if tetracycline (a kind of antibiotics) is taken during the development of teeth, the teeth formed will be greyish-blue to brownish-yellow.

Treatment: Laminate Veneer , Bleaching

2. Teeth appear to be greyish-black

Cause 1: Tooth decay

tooth decay
  • Treatment
    The dentist removes the tooth decay, and then puts on a filling.

Cause 2

pulp necrosis from injury
  • Pulp necrosis

    The pulp becomes necrotic because of tooth trauma or tooth decay, and the tooth will appear greyish-black.
  • Treatment
    Endodontic treatment called root canal treatment must be done to treat the discoloured tooth which has pulp necrosis and crowning of the tooth

If teeth still appear greyish-black, dentist can treat the discoloured teeth by bleaching, laminate veneer or crown.

  • Brownish-yellow or white patches at the surface of a tooth

  • Disturbance during the development of tooth
    If a deciduous tooth is so decayed that the pulp is exposed, the bacteria, via the apex of the tooth, will cause an infection in the vicinity of the developing permanent successor. This will disturb the development of the enamel of the permanent tooth, resulting in the formation of brownish-yellow patches.
  • Fluorosis
    Long term excessive fluoride ingestion will alter the development of the enamel of teeth. This disturbance will show as white patches on the teeth.


  • Disturbance during the development of a tooth or Fluorosis
    Treatments such as Filling, Laminate veneer or Crown.

  • Early tooth decay
    Dentist can apply topical fluoride onto the surfaces of teeth so that the early tooth decay lesion can be re-mineralised.


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