What is teeth whitening?

Teeth whitening involves bleaching your teeth to lighten the colour of the enamel.

The main ingredients used in tooth whitening products are the chemicals hydrogen peroxide or carbamide peroxide. The chemicals usually come in a gel, which is applied to your teeth. Sometimes a light is used too.

What causes discoloured teeth?

The outside of your teeth can be stained when you:

• drink tea, coffee or red wine
• eat food such as spices, berries or beetroot
• smoke cigarettes

The white enamel layer on the outside of your teeth can also wear away as you get older. This exposes the dentine layer underneath. This is a yellowish colour and causes your tooth to look yellower.

Teeth can also be discoloured on the inside if:

• they are damaged or injured
• you took certain medicines as a young child — including the antibiotics tetracycline or doxycycline

A tooth that has had root canal treatment can also become discoloured.

What are the benefits of teeth whitening?

If your teeth are stained or discoloured, you might want to whiten them. Teeth whitening can improve the appearance of discoloured teeth.

Where can I get my teeth whitened?

Only registered dental professionals can use the strong whitening gels and products containing more than 6% hydrogen peroxide.

The Australian Dental Association advises that only registered dental professionals have the training and knowledge to assess if bleaching is appropriate and safe for you. They are responsible for meeting safety and quality regulations. They can provide a professional assessment of your teeth.

Teeth whitening services may be offered by unregulated, unqualified professionals, such as in beauty and hair salons.

You can also buy teeth whitening kits online, in pharmacies or at the supermarket.

Using these kits or getting your teeth whitened by a non-qualified dental professional can put you at risk of harm. It's best for a dental professional to supervise or advise you on teeth whitening.

What does teeth whitening involve?

Your dental professional can provide treatment in their clinic or make you an 'at-home' teeth whitening treatment.

In-chair teeth whitening

Some whitening treatments can be done while you are sitting in the dental chair.

Your dental professional applies strong hydrogen peroxide gel. Often a light is placed over your teeth. You should have whiter teeth after one appointment.

If the problem causing the yellowing is deep inside your teeth, then a whitening gel applied to the outside of your teeth won't make your teeth whiter.

Sometimes a dental professional can do internal bleaching. This is done when teeth are stained on the inside after a root canal treatment. The whitening treatment is placed in the centre of the tooth, where the dental nerve used to be. It's left for several days before being cleaned out and fixed with a filling.

Take-home teeth whitening

With take-home teeth whitening, your dental professional will custom-make thin, plastic trays that fit over your teeth. They also give you some gel in the correct strength to suit your needs.

At home, you place the teeth whitening gel in the trays. Your dental professional will tell you how much whitening gel to use each time and how long to wear the trays for.

This method of teeth whitening takes longer to achieve results than in-chair treatment. This doesn't mean that the final result is better or worse.

How can I prepare myself for teeth whitening?

If you are considering teeth whitening, you should consult your dental professional to see if your teeth are suitable.

Teeth whitening is not recommended if you:

• are pregnant or breastfeeding
• have sensitive teeth
• have gum disease
• have cracks or holes in your teeth
• have untreated dental problems

Teeth whitening treatments will not work on teeth with

• crowns
• veneers
• fillings

What complications can happen?

Teeth whitening products containing high levels of bleaching agents should be used under the supervision of a dental professional.

If the teeth whitening product contains a lot of bleaching agent, it can cause irritation or burns to your:

• lips
• gums
• tongue

Your teeth may be sensitive to cold straight after treatment. Your gums and the inside of your mouth may also feel irritated. If this continues for more than 1 or 2 days you should see your dental professional for a check.

It's dangerous to swallow the product. Swallowing whitening gel can also cause nausea and stomach irritation.

If you have any cracks in your teeth, teeth whitening bleach could cause pain or further damage.

How much does teeth whitening cost?

The cost of dental treatments and procedures depends on many factors. Always ask how much a treatment will cost before you start the treatment.

Be sure to consider the safety of teeth whitening treatment and how well it works, not just the cost.

Are there alternatives to having my teeth whitened?

To avoid teeth staining, you can:

• clean your teeth with a toothbrush and floss every day
• don't smoke cigarettes
• rinse your mouth with water after having food or drink that can discolour your teeth

Some alternatives to teeth whitening treatment are:

• having your teeth cleaned by your dental professional
• dental treatments such as veneers or crowns
• using whitening toothpaste
• using natural alternatives

Tooth whitening toothpaste

Whitening toothpastes can reduce stains on the outside surface of your teeth. The toothpastes contain special abrasives or whitening agents.

Some ingredients are:

• sodium hexametaphosphate
• hydrogen peroxide
• phthalimidoperoxycaproic acid — sometimes called PAP

It's best to use a soft toothbrush with toothpaste to avoid damaging your tooth enamel.

Whitening toothpaste can also make your teeth sensitive.

Natural teeth whitening

Some research suggests that natural ingredients may help whiten teeth. These include:

• Bicarbonate of soda or baking soda
• Charcoal
• Fruits such as lemons, strawberries, oranges and papaya

However, using these often may damage your teeth. If you would like to whiten your teeth, it's best to speak to a dental professional.