Do Whitening Toothpastes Actually Work?

The commonest whitening mechanism is abrasion. The paste contains fine particles (silica is typical) that polish stain off the outer surface of the enamel. Stain from tea, coffee, tobacco and paan sits on that surface, so a paste can genuinely lighten a mouth that is coated with it.

That is also the limit. Abrasion removes what has been deposited on the tooth. It does nothing to the colour of the tooth itself, and a paste that polishes harder is not a paste that whitens more, because past a point it is simply wearing the enamel.

A professional scaling and polish does the same job far more completely in one visit. If your teeth look dull and stained, that comes first. See what scaling involves.

Some pastes list a peroxide. The contact time is the problem: you brush for two minutes and spit it out, so the peroxide is on the tooth for a tiny fraction of the time a professional gel or a tray sits there. Any effect is small, and the legal concentration in a consumer paste is deliberately low.

Others use a blue-tinted pigment (blue covarine is the usual name) that leaves a very thin film on the enamel. Yellow and blue offset each other, so the tooth looks whiter and less yellow under the light. Nothing in the tooth has changed. The effect fades as the film wears off, typically within hours of brushing.

None of this is dishonest, as long as you know which one you are buying. Check the ingredient list for what the paste actually relies on, and treat the promise on the front of the tube as marketing.

It cannot lighten the shade of the tooth. The yellow you see is mostly the dentine underneath showing through enamel, and that responds to peroxide whitening, not to brushing. If that is your problem, read whether professional whitening is safe and the page on yellow teeth.

It cannot whiten crowns, veneers or fillings, and it cannot remove stain that is built into the tooth (tetracycline, fluorosis, a darkened tooth with a dead nerve).

It cannot fix the habits that stain. Sipping tea through the day and tobacco will out-stain any paste.

Abrasivity varies widely between pastes. Sustained use of a strongly abrasive paste, combined with a hard brush and heavy pressure, wears enamel and exposes the yellower dentine, which defeats the purpose. Charcoal pastes sit at the risky end of this range.

Warning signs are new sensitivity to cold, a smooth glassy look at the gum line, or notches where the tooth meets the gum. If you see them, stop the whitening paste and have the teeth looked at.

A sensible choice is a fluoride toothpaste with moderate abrasivity, used twice a day with a soft brush and light pressure. If you want it to whiten a little as well, fine. Do not buy it expecting a shade change.

If you have used a whitening paste for a month and see nothing beyond a cleaner surface, the remaining colour is inside the tooth. Whitening treatment is the next step. Professional treatment can be done in the chair or with take-home trays, and the cost ranges are on the teeth whitening cost page.

For a wider plan that includes shape and colour, the smile design service is where the options are laid out, least invasive first.