Is teeth whitening safe? An honest answer
Whitening is one of the most requested and most misunderstood treatments in dentistry. What the evidence says, and where the real risks sit.
Cosmetic & Prosthodontic Dentist
The short answer: dentist-supervised whitening at regulated concentrations has decades of evidence behind it and does not damage enamel. The risks people worry about and the risks that actually exist are different things.
What whitening does
Peroxide gel diffuses through the enamel into the dentine underneath and breaks down the pigmented molecules that have accumulated there over years. It changes the colour of your existing tooth structure — it does not coat, strip or resurface anything.
This is also why it has limits. Whitening lightens natural tooth structure only. Crowns, veneers, composite fillings and bonding will not change colour at all, which matters enormously if you have visible restorations.
Where the real risks are
Every one of these is avoided by having a check-up first. That is the entire reason we insist on it, and it is not a formality.
- Unregulated products bought online, which can contain many times the legal peroxide concentration and cause chemical burns to the gums
- Beauty salon whitening delivered by people with no dental training and no ability to diagnose what is under the enamel
- Whitening over untreated decay or a leaking filling, where gel reaches the nerve directly and causes severe pain
- Whitening with active gum inflammation, which turns manageable sensitivity into a genuinely miserable fortnight
Sensitivity
Around half of patients get some sensitivity to cold during a whitening course. It is temporary, it does not indicate damage, and it resolves within a few days of finishing.
It is also manageable. Shortening the wear time, skipping a night, and using the desensitising gel we provide will usually let you complete the course comfortably.
How much whiter, realistically
Most people move three to six shades on the standard guide. Yellow discolouration responds best; grey responds least; tetracycline staining from childhood antibiotics is the hardest of all and may need veneers instead.
We photograph your starting shade against a guide so the result at the end is documented rather than debated. If we do not think whitening will get you where you want to be, we will say so before you pay for it.
This article is general information written by a clinician at Dental. It is not a diagnosis and it does not replace an examination. Dental conditions that look similar can have entirely different causes — if something is worrying you, book an appointment. Read our full medical disclaimer.