Your teeth can also be stained on the surface through food and drinks such as tea, coffee, red wine and blackcurrant. Smoking can also stain teeth.

Calculus or tartar can also affect the colour of teeth. Some people may have staining under the surface, which can be caused by certain antibiotics or tiny cracks in the teeth which take up stains.


What does tooth whitening involve?
Professional bleaching is the most common form of tooth whitening. Your dentist will be able to tell you if you are suitable for the treatment, and will supervise it if you are. First the dentist will put a rubber shield or a gel on your gums to protect the soft tissue. They will then apply the whitening product to your teeth, using a specially made tray which fits into your mouth like a gum-shield.

The ‘active ingredient’ in the product is usually hydrogen peroxide or carbamide peroxide. As the active ingredient is broken down, oxygen gets into the enamel on the teeth and the tooth colour is made lighter.


How long does this take?
The total treatment can usually be done within three to four weeks. First, you will need two or three visits to the dentist. Your dentist will need to make a mouthguard and will take impressions for this at the first appointment. Once your dentist has started the treatment, you will need to continue the treatment at home. This means regularly applying the whitening product over two to four weeks, for 30 minutes to one hour at a time.

However, there are now some new products which can be applied for up to eight hours at a time. This means a satisfactory result can be achieved in as little as one week.


What other procedures are there?
There is now laser whitening or ‘power whitening’. During this procedure a rubber dam is put over your teeth to protect the gums, and a bleaching product is painted onto your teeth. Then a light or laser is shone on the teeth to activate the chemical. The light speeds up the chemical reaction of the whitening product and the colour change can be achieved more quickly using this procedure. Laser whitening can make teeth up to five or six shades lighter.


How long does this take?
Your dentist will need to assess your teeth to make sure that you are suitable for the treatment. Once it has been agreed, this procedure usually takes about one hour.


How much does tooth whitening cost?
You cannot get whitening treatments on the NHS. Private charges will vary from practice to practice and region to region. Laser or power whitening will be more expensive than professional bleaching. We recommend you get a written estimate of the cost before you start any treatment.


How long will my teeth stay whiter?
The effects of whitening can last up to three years. However, this will vary from person to person. The effect is less likely to last as long if you smoke, or eat or drink products that can stain your teeth. Ask your dentist for their opinion before you start the treatment.


What are the side effects?
Some people may find that their teeth become sensitive to cold during or after the treatment. Others report discomfort in the gums, a sore throat or white patches on the gum line. These symptoms are usually temporary and should disappear within a few days of the treatment finishing.

If any of these side effects continue you should go to your dentist.


What about home kits?
Home kits are cheaper. But because tooth whitening is a complicated procedure you should only have it done by a dentist, after a thorough examination and assessment of your teeth.

Over-the-counter kits sold in the UK are not recommended as they usually contain only a small concentration of hydrogen peroxide (the whitening product). The legal limit in the UK is 0.1% of hydrogen peroxide and effective bleaching products need to have about 3.6%. So home kits will not be able to lighten your teeth noticeably. Also, some contain mild acids and others are abrasive. This can cause ulcers and damage to the gums if the product is not used properly


What about whitening toothpastes?
There are several whitening toothpastes on the market. Although they do not affect the natural colour of your teeth, they may be effective at removing staining and therefore may improve the overall appearance of your teeth. Whitening toothpaste may also help the effect last, once your teeth have been professionally whitened.

We recommend that you look for our accreditation symbol on the packaging of oral care products. This is a guarantee that the claims made about the product have been scientifically and clinically checked by an independent panel of experts.


Can a single tooth which has been root filled be whitened?
Yes. Many dead teeth go discoloured after a root filling. If the tooth has been root treated, the canal (which previously contained the nerve) may be reopened. The whitening product is applied working from the inside to whiten the tooth.


When might tooth whitening not work?
Tooth whitening can only lighten your existing tooth colour. Also it only works on natural teeth. It will not work on any types of ‘false’ teeth such as dentures, crowns and veneers.

If your dentures are stained or discoloured visit your dentist and ask for them to be cleaned. Stained veneers, crowns or dentures may need replacing; again ask your dentist.


How can I look after my teeth once they have been whitened?
You can help to keep your teeth white by cutting down on the amount of food and drink you have that can stain teeth. Don’t forget, stopping smoking can also help prevent discolouring and staining.