Dental bleaching (or dental lightening) aims to lighten teeth colour.

External bleaching

  • "Homebleaching" ambulatory bite relief pads

The dentist produces an impression before preparing the bite relief pads that will be worn either during the day or at night, for about 10 to 15 days, depending on the staining of the teeth.  These low concentration products have been used for several years and are almost risk-free. Light soreness might be felt, but will disappear after the end of the treatment.

  • "In office bleaching" – dental operatory session

It is the quickest technique. Products are much more concentrated. The duration of the session is between half an hour and an hour. Should the teeth be greatly stained, two sessions with a two-week break are necessary for a good result.  

Internal bleaching

Internal bleaching consists in lightening a tooth devitalized from the inside. Devitalized teeth often look darker and are pretty unsightly, especially if it is an upper central incisor. In this case, we may apply an adequate product inside the tooth, if the root canal filling is waterproof. We might apply this product several times until we get the right tooth colour. If the teeth are considerably stained, it is sometimes essential to combine internal and external bleaching. 

Action products and mechanisms

Several techniques exist to lighten teeth. Most of them are based on hydrogen peroxide, which bleaches teeth pigments, particularly yellowish pigments.


  • Local contraindications: teeth to be bleached must absolutely be healthy and cavity-free. Indeed, the product would infiltrate decaying teeth. This should be avoided.
  • Bleaching products take effect by demineralising the superficial layer of the enamel. Risk of dental sensitivity is increased during and after the treatment.
  • Equally, a smoker who wants to lighten his teeth, yellowed by tobacco, will have to stop smoking beforehand, otherwise staining may come back.

Coffee, red wine and other strongly pigmented products must be avoided. 

General contraindications : avoid bleaching for pregnant women and children under the age of 18.


  • Healthy teeth, cavity-free.
  • Patient with good oral hygiene.
  • Staining due to antibiotics (tetracycline) taken by the mother during her pregnancy.
  • Former smoker.