Does teeth whitening cause sensitivity?

Why whitening can make teeth sensitive

Whitening gels use hydrogen peroxide or carbamide peroxide. These move through the enamel and the layer beneath it, called dentin, to break down stain molecules. Along the way, they can temporarily make the dentin more permeable, so the nerve reacts more to cold, air or touch.

Sensitivity is more likely if you already have sensitive teeth, gum recession with exposed roots, worn enamel, cracks, or leaky fillings. Strong gels and long sessions also raise the chance.

Check-up first

Before whitening, it helps to have an exam. Cavities, cracks and gum recession can make whitening uncomfortable and should be treated first. The dentist will also check your fillings, crowns and veneers, since these materials don't lighten and may not match your new shade.

Whitening isn't usually recommended during pregnancy or breastfeeding, or for young children.

Ways to reduce sensitivity

• Start using a toothpaste with potassium nitrate or stannous fluoride for two weeks before whitening
• With take-home trays, wear them for shorter periods or every second day
• Use only the amount of gel your dentist recommends; overfilled trays let gel touch the gums
• Stop for a day or two if teeth feel sore, then restart
• Avoid very cold drinks and acidic foods during the whitening period
• Ask about a fluoride gel or varnish to calm sensitive areas

In-office or take-home

At our office, whitening can be done in the chair, with dentist-prescribed take-home trays, or a combination of both. In-office whitening uses a stronger gel with the gums protected, so you see a change in one visit. Take-home trays are custom-made to fit your teeth and use a milder gel over a couple of weeks, which some people with sensitive teeth find easier.

Store-bought strips and kits can also cause sensitivity, and they don't come with an exam to rule out problems first.

Keeping your results with less sensitivity

Once you've reached the shade you want, you don't need to keep whitening constantly. Brushing with a fluoride toothpaste, rinsing with water after coffee or tea, and keeping up regular cleanings help keep teeth bright.

If you do touch-ups later, use the same gentle approach: shorter sessions, fewer days in a row and a sensitivity toothpaste. Keep your custom trays clean and in their case so they fit well for future use. If touch-ups start causing more sensitivity than before, mention it at your next checkup in case something else, such as a new cavity or receding gum, is the cause.

Related services

More patient guides

• Baby teeth care: a timeline from birth to age six
• What causes bad breath, and what can you do about it?
• Canker sore or cold sore: how to tell the difference
• Canadian Dental Care Plan: who qualifies and how it works

Trusted health information

• Caring for your teeth and mouth (Government of Canada)
• Oral health (Government of Canada)