Sinsational smile whitening
Professional tooth whitening uses peroxide gel to break down some external and internal stains after the dentist checks your teeth and gums.
The short answer
Professional tooth whitening uses peroxide gel to break down some external and internal stains after the dentist checks your teeth and gums. It changes the colour of natural enamel, not the shade of fillings, crowns, or veneers.
What does peroxide whitening do to stained teeth?
Whitening is a chemical treatment using hydrogen peroxide or carbamide peroxide. The material diffuses through enamel and dentine and oxidises stain molecules; the result depends on stain type, tooth structure, and the chosen protocol.
What should be checked before professional whitening?
Have the dentist assess decay, leaking restorations, gum disease, cracks, and sensitivity before whitening. Follow the supplied wear time or in-clinic instructions, and reduce strongly staining foods while the teeth are sensitive.
When should whitening symptoms be reviewed by a dentist?
Seek dental advice for sharp pain, persistent sensitivity, gum irritation, uneven colour, or a tooth that does not respond like the others. Whitening is not the right first step when darkening may come from decay or a dead pulp.
What should you ask before choosing whitening treatment?
Ask what caused the staining, whether existing restorations will need colour matching, and which peroxide concentration and application method are planned. Ask how sensitivity will be managed and when a review is needed.
Frequently asked questions
Will whitening change a crown?
No. A crown keeps its material shade, so the dentist may need to plan colour matching before treatment.
Why can whitening cause sensitivity?
Peroxide can temporarily affect fluid movement through enamel and dentine, stimulating the tooth nerve in some people.
Who wrote this page
This library is published by Dental Nation, a licensed dental group practising in the United Arab Emirates. Pages are written and overseen by the same clinical team that treats patients in our clinics, and are held to a fixed editorial standard for safety and accuracy.
This page is patient education, not medical advice, and cannot replace an examination. Anything urgent — facial swelling, trauma, uncontrolled bleeding or severe pain — needs a dentist or emergency care now.