Tooth Whitening

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A mild bleaching agent known as carbamide peroxide or urea peroxide can be used for whitening teeth. A recommended procedure involves applying the preparation to the teeth in a specially designed and fitting mouthguard.

What can be expected?

Before Treatment

After Treatment

If your dentist finds that your teeth are suitable for the procedure the type of change to the right can be achieved.

What is involved?

Step 1
An impression (mould) is made of your teeth.

Step 2
A special thin mouthguard is made to fit your teeth accurately. It only covers teeth and does not extend onto your gums.

Step 3
The whitening agent comes in a gel form. At home, or wherever convenient, place a small amount of the gel in the mouthguard and wear it for the period of time recommended by your dentist.

Step 4
A typical routine is to wear the mouthguard 1 to 2 hours a day for a few weeks.

It is best to avoid the type of mouthguards sold over the counter for bleaching. Invariably they do not fit well and, as a result, allow bleaching gel to wash away from your teeth.


Whitening procedures containing 10 per cent urea peroxide are regarded as being safe and effective if used according to directions. There have been some reports of mild and temporary effects such as gum irritation and a burning sensation in the throat and palate. A correctly fitting mouthguard that does not cover the gums and fits snugly to the teeth will help minimise these problems. To avoid unnecessary contact with the palate and throat use only small amounts of bleaching gel. In addition your dentist will show you how to wipe away any excess material once the mouthguard is seated.

Teeth may become sensitive if your dentist’s instructions are not followed and the mouthguard is worn too many hours a day.

The material does not harm the teeth or existing fillings.

It has been suggested that the procedure not to be used by pregnant or lactating mothers.

How successful is it?

For such a simple procedure the long-term results are very good. On occasions some teeth will require a touch up after 4-6 months. For others, one course of treatment is sufficient to last for years. At the finish of treatment it is customary for the teeth to be slightly whiter than required. Over the next week or so they settle back into their new shade.

What are the Limitations?

There are a number of situations where the teeth are discoloured but where tooth whitening is not the appropriate treatment. For example:

When some types of chronic ulcerations are present in the mouth.

Where the teeth have a deep in-built stain. Antibiotic-stained teeth are particularly resistant to the whitening procedure. However, in some cases some improvement has been obtained.

A single dark tooth (although a different type of bleaching procedure is often used as part of treatment).

Discolouration produced by hidden decay

Stained calculus between the teeth.


On occasions bleaching may result in the teeth not whitening evenly. In these situations an alternative form of treatment may be required.

Tooth whitening will not make old fillings lighter. Dark fillings may need to be resurfaced or replaced once the teeth have settled into their new colour.

Why a check-up first?

A dental check-up is required to make sure your teeth are suitable for tooth whitening. As seen in some of the photos above there are conditions for which the treatment is not appropriate.

Source: “Thinking of having tooth whitening?” Dental Health Foundation Australia