What is teeth whitening?

Teeth whitening involves bleaching the teeth to lighten their colour. After treatment, the teeth look a few shades whiter, but not usually bright white.

Teeth whitening is an optional procedure — it is very rarely a necessity.

Whitening products typically use the chemicals hydrogen peroxide or carbamide peroxide. Only registered dental practitioners can legally use the most concentrated — and thus most effective — whitening solutions.

The bleach soaks through the tooth’s enamel top layer and into the dentine, the main part of the inside of the tooth which is slightly softer than the enamel. The bleach reacts with the coloured molecules that cause discolouration. The dentine then becomes lighter and the teeth look whiter. Bleach can also make the enamel surface more reflective, which looks whiter too.

When might someone need teeth whitening?

Teeth can be discoloured by:

• tea, coffee, red wine or cola
• smoking
• excessive fluoride or tetracycline (an antibiotic) when the teeth are forming

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

Teeth whitening is not recommended if you:

• are pregnant or breastfeeding
• have sensitive teeth
• have gum disease or shrinkage
• have cracks or exposed dentine

Note that whitening treatments will not whiten existing crowns, veneers or fillings.

Teeth whitening is also offered by unregulated, unqualified practitioners, for example in beauty and hair salons, shopping malls, salons, or via mobile services. Many non-dental practitioner teeth whitening services claim that their practitioners are “teeth whitening specialists” who have the knowledge or training to perform teeth whitening procedures safely. However, the Australian Dental Association advises that only registered dental practitioners have the expertise to assess whether bleaching is safe for you, to recommend the most appropriate technique and materials, and to provide treatment that meets safety and quality regulations.

What happens during a teeth-whitening procedure?

Bleaching

Your dentist will first create moulds of your top and bottom teeth. These are used to make customised trays, like a mouthguard, that fit over your teeth.

At your next appointment, bleaching gel is put into the trays, which you wear in your mouth for 15 to 30 minutes. The dentist might also shine a light to speed up the whitening process. Often, the treatment is repeated at home, following the dentist’s instructions. You’ll probably notice a difference in 2 to 4 weeks.

Another option is to get a kit with the customised trays from your dentist and carry out the treatment at home.

Power bleaching

Power bleaching, also known as laser whitening, is done in the clinic. The dentist covers your gums and then paints bleaching agent on the teeth. A laser light is shone to activate whitening. This takes about 60 minutes, and often only needs one treatment.

What to expect after a teeth-whitening procedure

Whitening is generally successful and can last for several years, but it isn’t permanent: for example, tea, coffee and red wine can stain your teeth again.

Benefits and risks of a teeth-whitening procedure

Teeth whitening can improve the appearance of discoloured teeth. It is also cheaper than some other restorative procedures. However, make sure you find out about the cost, risks and likely outcome before going ahead with treatment.

The most common side-effects, which are often temporary, include:

• tooth sensitivity, especially from power bleaching
• irritation of the gums

How much does it cost to get teeth whitened?

• bleaching at the dentist’s clinic with home follow-up costs $500 to $1500 each for the top and bottom arch
• bleaching at home with trays supplied by the dentist costs $250 to $450 per arch

Alternatives to teeth whitening

If you’re not happy with your teeth, alternatives include:

• having your teeth cleaned by the dentist
• using whitening toothpaste
• dental restoration, such as veneers or crowns