Tooth Whitening


What is tooth whitening?

Dental bleaching or tooth whitening is a method of lightening the colour of natural teeth. The shade of teeth varies between individuals and at different ages - teeth can gradually darken naturally over time due to drinking tea, coffee, red wine or smoking. Tooth colour is influenced by a person’s genetic makeup and by any surface stains or deposits in or on the teeth. If teeth are dark due to external stains or deposits, they will need to be cleaned before tooth whitening is undertaken.


We use the tray system because it is the best way to whiten teeth. Impressions are taken of your teeth to make a plastic whitening tray (similar to a very thin gum shield) that fits over and around your teeth. The gel is placed in the custom-made tray and worn as advised by the dentist, usually overnight for a number of nights. The teeth will become gradually lighter over time.

A course of treatment takes a variable number of weeks and results may vary depending on the initial darkness of the teeth, the concentration of the gel used and the frequency of application.

As all whitening treatments fade over time, we recommend following treatment you purchase further whitening gel to allow you to top up the new colour of your teeth and keep them looking as bright as they were when you finished your whitening treatment.

A gel, normally carbamide or hydrogen peroxide, is used to whiten teeth. Chlorine Dioxide whitening products should never be used because they strip the surface of the teeth, making the teeth much more prone to further staining.

Is it safe and what are the risks?

Tooth whitening is incredibly safe and of course minimally invasive. There is a risk that the whitening process will not work quickly and the dentist will discuss the possible reasons why this might not work particularly well or why it might take longer than average. Not all teeth whiten to the same extent, particularly deeply discoloured teeth.

Some teeth lighten more effectively or more quickly than others. Teeth which are already quite white only lighten a little further. Some teeth do not whiten evenly. This can be a problem where the gum has receded, and the darker root surface is exposed. Such teeth or worn teeth can become sensitive with whitening. 

Certain types of tooth discolouration do not respond quickly and require special treatment by a dentist. Fillings, veneers, crowns and bridges that match the existing teeth will not change colour with whitening. The cost of replacing these so that they match the new lighter shade of the natural teeth can be considerable and should be discussed with the dentist before whitening is undertaken.

Extensive clinical data continues to support the safety and effectiveness of tooth whitening, but during the process, teeth may become sensitive for a period of time. This is usually only temporary, and a desensitising toothpaste can be placed in the tray and worn for up to 30 minutes before and after each whitening period to minimise the sensitivity.

Temporary irritation of the soft tissues in the mouth, particularly the gums, is rare but can occur if too much gel is loaded into the trays.

Candidates for professional tooth whitening

Eligibility for treatment is gathered during your consultation and screening. While many individuals will qualify for treatment, not all people suitable candidates for the procedure. Certain drugs when taken at the time the teeth are forming, e.g. tetracycline can stain the teeth which is very difficult to reverse. If this is the case, the dentist will discuss their finding with you and advise on other possible treatment options.  

How long does the lighter appearance last?

Teeth that have been whitened have a tendency to return to their original colour eventually. The time this takes depends on a patient’s diet and whether they smoke. The shades obtained would be expected to be maintained for between two and four years, but patients who regularly eat darker foods and smoke will darken their teeth more quickly. Teeth will require to be “topped up” from time to time, just remember to keep hold of your trays!

Davinder Raju.


Davinder Raju