The low down on Teeth Whitening

Over the counter vs. professional whitening systems

There are several ways to help whiten and brighten your teeth; however some ways are more effective and safer than others. Before whitening your teeth, it is important to have a dentist assess your suitability for treatment. Tooth whitening is not recommended if you have decay or gum disease and is ineffective for whitening fillings and crowns or veneers. However, it is possible to change restorative work post-whitening to match your new, bright smile.

Whitening Products Can Be Divided Into Two Categories

  1. Peroxide-containing bleaching products that change the colour of the tooth or
  2. Products that remove surface stains but don’t change the tooth colour.

Professional bleaching

Here, at North Sydney Dental Practice we take moulds of your teeth and use those to create custom trays that fit of your teeth. Medical grade peroxide is applied to the tooth and held in place by these trays. We use carbamide peroxide which breaks down into hydrogen peroxide and urea. The peroxide reacts with existing stains and discoloration, changing their chemical structure so that they’re no longer coloured. Either 10% carbamide peroxide for 8-10 hours (overnight) or 20% carbamide peroxide for 3-4 hours can be used.

During the whitening process tooth sensitivity is often experience. This is temporary and will stop after treatment. If used incorrectly tissue irritation can also occur. This is also temporary, but if it occurs it is best to re-read the instructions and ensure that your custom trays fit well.

Over the counter products


Over the counter products bought at chemists and supermarkets are often ineffective as they use acids instead of peroxide gels to whiten the teeth. Some are paint on materials and some require you to ‘boil and bite’ (heat the gum shield supplied and then mold it to your teeth). This does not guarantee a custom fit and can lead to the product leaking and causing harm.

Additionally there are non-bleach whitening toothpastes available that can remove the surface stains. Charcoal toothpaste falls into this category as it has an abrasive quality but doesn’t change the colour of the tooth.

Bleach-containing toothpastes such as Colgate Optic White, which contains 1-2% hydrogen peroxide, can be effective for minimally brightening teeth. As it is only applied for the 2 minutes while brushing the active ingredient doesn’t get much time to do its job!

NB: 10% carbamide peroxide yields approximately 3.5% hydrogen peroxide.

Tips to keep your teeth white

  1. Avoid foods and drinks that stain e.g. coffee, tea, red wine, curry and tomato based sauces such as bolognaise.
  2. Drink a glass of water after eating and drinking (especially highly coloured foods and drinks)
  3. Floss and brush thoroughly and regularly
  4. Visit your dental practice every 6 months for a professional clean and removal of extrinsic stains

For further advice on oral health and how to maintain your teeth and gums, read our previous article on the 9 foods and drinks to avoid for healthy teeth.

North Sydney Dental Practice
Suite 201, Level 2, 83 Mount Street, North Sydney NSW 2060
02 9922 1476

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