If whitening used to work on your teeth and has stopped, that is not a failure of the product and buying a stronger one will not fix it. The colour has moved somewhere whitening cannot reach.
Where the colour actually is
Enamel is translucent and largely colourless. Most of what you see as tooth colour is the dentine underneath, showing through.
Enamel thins over decades of brushing and acid exposure, while dentine simultaneously darkens and lays down more of itself. So more dark tissue shows through less covering. Whitening works on the enamel, which is not where the problem is.
What else causes it
A tooth that has had a root canal darkens from within, and needs internal whitening rather than external, which is a different procedure entirely.
Tetracycline banding from childhood antibiotics responds to whitening only partially and over months rather than weeks. Old composite fillings do not whiten at all, and become more obvious as the teeth around them lighten.
What still helps
It is worth one properly supervised attempt with custom trays before concluding it will not work, because home strips underperform badly and many people have only tried those.
Expect a modest improvement, and treat it as establishing the baseline for whatever comes next.
When restoration is the honest answer
If supervised whitening produces little, the options are veneers or bonding, which change the colour by covering it. That is a bigger decision and should be presented as one.
What we would not do is sell you three more rounds of whitening that the assessment already suggests will not deliver.
One supervised attempt tells you which situation you are in. If the colour is in the dentine, no whitening product will reach it, and knowing that saves both money and months.
Questions about your own case? Send us your photos and we will walk you through the options.
