Updated August 2026 · Clinically reviewed by [Reviewer name], DDS — licence #000000
Whitening works extremely well on some kinds of staining and does almost nothing for others. Knowing which kind you have before you pay for treatment saves money and disappointment.
The core distinction
Extrinsic staining sits on the surface of the enamel and comes from what you consume — coffee, tea, red wine, tobacco, certain foods. It responds well to peroxide-based whitening at almost any concentration.
Intrinsic discoloration sits inside the tooth itself. Whitening gel can’t reliably reach or affect it, no matter the concentration or how long you use it.
| If your teeth are… | Likely cause | Will whitening help? |
|---|---|---|
| Evenly yellowed, worse near the gumline | Surface staining, aging | Yes, typically |
| Yellow-brown after years of coffee or tea | Surface staining | Yes, typically |
| Grey or blue-grey overall | Often tetracycline exposure | Rarely, see a dentist |
| White or brown mottled patches | Often fluorosis | Rarely, see a dentist |
| One tooth darker than the rest | Trauma or a past root canal | No, needs other treatment |
| Crowns, veneers, or bonding | Restoration material | No, does not respond |
Tetracycline staining
Caused by tetracycline antibiotics taken during childhood tooth development, or by a mother during pregnancy. It produces grey or banded discoloration that sits deep in the dentine. Whitening can improve mild cases slightly over months of consistent, dentist-supervised treatment. Moderate to severe cases typically need veneers or bonding instead.
Fluorosis
Caused by excess fluoride exposure during childhood tooth development, usually from water or supplements. It produces white flecks or brown mottling. Very mild fluorosis sometimes responds partially to whitening; visible mottling generally does not.
A single dark tooth
If one tooth is noticeably darker than its neighbours, the most common cause is trauma to that tooth at some point — sometimes years earlier and long forgotten — or a root canal treatment that has darkened the tooth from the inside. Whitening the whole set won’t correct a single tooth like this, and can make the mismatch more visible. This needs a dentist’s assessment, and the fix is usually internal bleaching, a crown, or veneers on that tooth specifically.
Restorations don’t whiten
Crowns, veneers, bonding, and large fillings are made from materials that don’t respond to peroxide at all. They stay exactly the shade they were made. If you whiten your natural teeth around an existing restoration, the restoration will increasingly stand out rather than match — sometimes badly. If you have visible restorations on front teeth, mention this before starting any whitening treatment.
If you’re not sure which category you fall into, a consultation is worth the visit even if you end up whitening at home afterward. A dentist can tell in a few minutes whether your staining is a good candidate for whitening at all.
Common questions
I tried an at-home kit and saw no change. Does that mean nothing will work?
Not necessarily, but it’s a strong signal your staining may be intrinsic rather than surface-level. A dentist consultation can confirm which type you have and what options exist beyond whitening.
Can veneers or bonding be whitened later if I change my mind?
No. Once placed, they stay their original shade permanently. If you’re considering both whitening and restorative work, doing the whitening first and matching restorations to the new shade afterward is the usual approach.
Is intrinsic staining a sign of a health problem?
Not usually. Tetracycline staining and fluorosis both relate to childhood exposure and aren’t ongoing health concerns. A single dark tooth from past trauma is also not urgent on its own, though it’s worth having a dentist confirm there’s no underlying issue.