What is tooth whitening?
Tooth whitening is a cosmetic treatment that changes the colour of your teeth so that they look brighter. Your dentist will use a chemical gel (containing hydrogen peroxide or carbamide peroxide) to change the shade. The dentist can either apply the gel either inside a tooth (where a tooth has died off and has become darker as a result) or, more usually, on the surface.
NB: The degree of colour change will vary from person to person.
How does tooth whitening work?
That depends on the type of tooth whitening your dentist is proposing to do:
Sometimes a tooth darkens from the inside because of an infection. Then, the dentist will put the whitening chemicals inside the tooth. This is called non-vital tooth whitening. This can be done either before or after you have root canal treatment (you will need
root canal anyway because of the infection).
Dentists whiten the outer surface of a healthy tooth in one of two different ways:
- Take home tooth whitening kits: As the name suggests, this involves you using a special kit at home. Before tooth
whitening starts, your dentist will do a dental examination to make sure that everything is
healthy. Provided there aren't any problems that need to be addressed first, your 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 to fit exactly over your teeth. Your dentist will also record the colour of your teeth using a special shade guide so that he/she can measure how much the colour has changed when you are reviewed.
At the next appointment, your dentist will provide you with the dental trays and the tooth whitening kit 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 colour 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 normal colour of the teeth. Rather than make special trays, your dentist will paint a special protective coating on your gums to keep the whitening gel away from them. Dental "cheek retractors" are used to keep the cheeks and lips clear, too.
Your dentist will apply a concentrated tooth whitening gel to the teeth and will catalyse (speed up) the whitening reaction using an 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 reapply the gel until it the colour is as you want (usually subject to a maximum of three applications at one visit).
How white will my teeth become?
This depends on the colour they are to begin with and why they have darkened.
Teeth have natural colour variations - some are whiter than others to begin with - a bit like the natural variations in the darkness of people's skin or hair. If your teeth are naturally darker in colour, they won't necessarily become as bright as someone else's after tooth whitening - unlike hair colouring, there is a limit to just how much you can bleach a tooth.
However, teeth that are naturally pale but have darkened from 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 after your dental examination.
How long does tooth whitening take?
For take-home kits, this depends on how dark the teeth are when whitening starts and how much colour change is desired, but it is usually between 10 days and 3 weeks.
In-surgery tooth whitening usually takes the dentist 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?
How long the teeth remain a lighter shade isn't just down to your dentist - this is greatly influenced by factors under your own control -
e.g. how well you clean your teeth, whether you smoke or not, or drink large amounts of tea, coffee or red wine, etc. Nonetheless, you shouldn't need to have tooth whitening again for 2 to 3 years, and possibly a lot longer.
Is tooth whitening safe?
Your dentist will check the health of your teeth and gums before whitening starts. This helps to minimise the risk of discomfort (this can result from the application of whitening chemicals to decayed or damaged teeth).
Nonetheless, it is quite common for people to experience some dental sensitivity for a few days after tooth whitening
(e.g. discomfort when drinking hot or cold drinks). This sensitivity can be reduced by applying toothpaste for sensitive teeth. It will subside in time.
For in-surgery tooth whitening the dentist protects your gums with a special shield chemical that keeps the whitening gel away from them, avoiding irritation of the soft tissues in the mouth.
Other than this, there are no significant risks associated with tooth whitening.
What does tooth whitening cost?
Guidelines to costs are listed in our Independent Fee Schedule. Please click
here if you wish to view this.