How Does Teeth Whitening Work?

Teeth whitening uses a peroxide-based gel to break down the stains trapped in your enamel, lightening the colour of your teeth. Here's the science, minus the hype.

Why teeth stain

The outer layer of a tooth — the enamel — has microscopic pores that absorb colour from coffee, tea, red wine, and tobacco. Age and certain medications add to it. Over time these stains sink deeper and become harder to brush away.

How whitening works

Most whitening products use hydrogen peroxide or carbamide peroxide as the active ingredient. These break down into oxygen molecules that pass into the enamel and split apart the stain molecules. The colour lifts, and your teeth look brighter.

Professional vs over-the-counter

Professional whitening, supervised by a dentist, uses a controlled concentration and can lighten teeth by several shades in a single visit. Over-the-counter strips and gels are weaker and typically lift two to three shades. Some also dry out the teeth, which makes them look lighter for a short while until the tooth rehydrates — so the effect is less lasting.

Is it safe for enamel?

Done correctly, whitening doesn't damage enamel. Professional treatment is supervised so the right concentration is used and your gums are protected. Whitening agents don't change the colour of crowns, veneers, or fillings, and anyone with sensitive teeth or gum disease should get advice first.

A long history

People have tried to whiten their teeth for thousands of years — ancient Egyptians used a mix of ground pumice and vinegar. Today's peroxide-based methods are far more effective and comfortable.

Curious whether whitening suits you? Book a teeth whitening consultation, or read the benefits of professional whitening.