Is teeth whitening safe? A dentist answers
How whitening works, and why it does not wear enamel away
Whitening gel contains hydrogen peroxide or carbamide peroxide. It releases oxygen that moves into the enamel and breaks up the stain molecules inside the tooth, so the colour lightens without anything being drilled or removed.
Whitening is not sanding and it does not peel a layer off. The tooth keeps the same shape and thickness; only the colour of the stains inside it changes.
The real side effects
Most people notice very little, but these can happen:
- Temporary sensitivity to cold or heat: the most common effect, and it usually settles within 24–48 hours.
- Mild gum irritation: this happens if gel touches the gums, which is why we place a protective barrier on the gums first.
- Colour mismatch with fillings or crowns: gel does not whiten fillings, crowns or veneers, so they can look darker next to the whitened teeth.
Who should wait before whitening?
A check-up before whitening matters, because in some cases we postpone it or treat something first:
- Pregnancy and breastfeeding: we advise waiting until afterwards.
- Cavities or broken fillings: gel can reach the nerve and cause pain, so we treat these first.
- Gum inflammation or heavy tartar: we clean first, and that is included in the Shade Studio session.
- Exposed roots or strong existing sensitivity: we use a gentler plan; see the sensitive-teeth whitening page.
- Young age: whitening is not for children, and teenagers are assessed after a check-up.
What actually harms your teeth
The real damage we see in the clinic usually comes from:
- Lemon, vinegar and baking soda: acids and abrasives that wear enamel down. Over time the tooth looks more yellow, because the layer under the enamel is darker.
- Charcoal and other abrasive toothpastes: they only remove surface stains, and heavy use wears enamel.
- Unbranded products bought online, or whitening too often: unknown strength and overuse.
- Whitening without a check-up: it can hide a cavity or gum problem that needs treatment.
How to whiten your teeth safely
At Shade Studio the session runs in this order: a check-up and shade record on the VITA guide, scaling and polishing, gum protection, professional whitening gel in timed stages, and then we measure the new shade. If you feel any sensitivity, we treat it in the same session.
For two days afterwards, avoid coffee, tea, hibiscus, dark sauces and smoking, because that is when teeth pick up colour most easily.