What does this mean?
Extrinsic staining collects in the pores of the enamel: coffee, tea, red wine and tobacco. It is superficial and responds well to a professional cleaning and to whitening.
Intrinsic discolouration comes from the dentine and behaves differently. As enamel thins, the yellow dentine beneath shows through; a tooth that died after trauma turns grey; tetracycline staining sits in bands. In this group whitening achieves only so much and veneers are often needed.
One tooth darker than the rest is a separate matter, usually related to that tooth's vitality.
Likely causes
What helps at home?
- Rinse with water after coffee and tea
- Avoid abrasive whitening pastes; they thin the enamel
- Stopping smoking removes the fastest-advancing cause of staining
- One tooth becoming clearly darker than the others
- Pain or a gum bump alongside the discolouration
- An area near the gum darkening quickly
- Roughness or a cavity you can feel on the surface
Frequently asked questions
- Does whitening damage enamel?
- Applied in clinical conditions at the right concentration, hydrogen peroxide does not erode enamel; it breaks down the pigment molecules in its pores. Unsupervised high-dose products can cause damage.
- Why has one tooth darkened?
- Usually because the pulp died after an earlier trauma. Such a tooth responds differently to whitening, and its vitality should be assessed first.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.