Take home tooth whitening kits
Also known as tray whitening, this involves using a special kit at home. Before tooth whitening starts, the dentist will examine your teeth and mouth to make sure that everything is healthy. Provided there aren't any problems that need to be addressed first, the dentist will take impressions (i.e. a mould) of your teeth. The dentist sends these to a specialist dental laboratory, who make flexible dental trays with a tiny air gap to allow the whitening gel to spread evenly over your teeth. The dentist will also record the shade of your teeth using a special calibrated guide so that he can measure how much the colour has changed when you are reviewed.

At the next appointment, your dentist will check that the trays are a good fit and will give you instruction in how to use them. The trays are usually worn at night while you are asleep. In the morning, you simply take them out and brush away the remaining gel. The tooth shade will gradually change and you continue to use the kit until the desired shade is achieved - your dentist will review your progress with you.
In-surgery tooth whitening
This procedure takes place in the dental surgery because the chemicals used are much more powerful. Before tooth whitening starts, your dentist will take a "shade" to record the starting colour of the teeth. Dental "cheek retractors" are used to keep the cheeks and lips clear. A concentrated tooth whitening gel is applied to the teeth and the whitening reaction is catalysed (speeded up) with intense light.

The gel is then cleaned off the teeth and the shade is checked. If you want more of a colour change, the dentist can repeat the process (subject to a maximum of three applications at one visit).

Why should I consider tooth whitening?
Many people like to whiten their teeth because it gives them a more youthful appearance: dark, discoloured teeth can be very unappealing. It often makes a tremendous difference to how your mouth looks - many patients feel it makes them look five to ten years younger.

It is also essential to consider tooth whitening whenever you are having a new crown, filling, veneer, denture or inlay. This is because teeth can be whitened but crowns, inlays, etc. cannot. If you have new crowns and then later decide you’d like whiter teeth you may need to have the crowns remade (at considerable expense) just to match your new tooth shade.
How white will my teeth become?
This depends on the colour they were to begin with and why they have darkened: the degree of colour change varies from person to person. Teeth have natural colour variations - a bit like the natural variations in the shade of people's skin or hair. If your teeth are naturally darker in colour, they won't necessarily reach the brightest white shade.

There is a limit to just how much you can whiten a tooth. Teeth that are naturally very white but have been stained by smoking, drinking red wine, tea, coffee, etc., are likely to whiten quite easily and to achieve a very bright white. Your dentist can give you a better idea of the likely shade change at your dental examination.
How long does tooth whitening take?
For take-home kits: usually between 14 and 20 days. In-surgery tooth whitening usually takes about an hour - but if your teeth are very dark and you want a lot of colour change, you may need to use a take-home kit after (in addition to) the in-surgery whitening.
How long does tooth whitening last?
This is determined by several factors – e.g. how well you clean your teeth, smoking, drinking tea, coffee or red wine, etc. As a rule of thumb, tooth whitening lasts about a year.
Does tooth whitening cause discomfort?
It is quite common for people to experience some sensitivity for a few days during or after tooth whitening. This can be reduced by applying toothpaste for sensitive teeth or special desensitising agents.
What does tooth whitening cost?
Tooth whitening with a take-home kit costs from £295.00. In-surgery tooth whitening costs from £285.00. In-surgery tooth whitening and take-home kit £500.00.
Are there any alternatives?
Whitening toothpastes can remove some superficial staining from the surface of teeth, but they do not really alter the fundamental shade of the tooth beneath. If you want to really brighten your teeth, the only effective way to do it is by using a dentist-supervised (take-home kit) or dentist-applied (in-surgery) tooth whitening system.

Crowns and veneers can also change the appearance of teeth, but they require a quantity of tooth to be removed in the preparation process. Modern preventive dentistry is all about preserving healthy tooth tissue, so crowns and veneers aren't the preferred treatment option if all that is required is a colour change.