Not all tooth discolouration is the same, and the distinction matters because it determines what will work. Stain sitting on the outside of the tooth responds to cleaning and whitening. Colour change within the tooth often does not, and pursuing whitening for it leads to disappointment and expense.
Extrinsic: stain on the surface
Enamel has a microscopic surface texture and an outer protein layer that pigments adhere to. Over time, that layer takes up colour from:
- Tea, coffee and red wine.
- Tobacco, smoked or chewed, and vaping to a lesser degree.
- Dark-coloured foods: curry, soy sauce, balsamic, berries, beetroot.
- Some mouthwashes, chlorhexidine in particular, which causes a characteristic brown staining with prolonged use.
- Iron supplements.
- Chromogenic bacteria, which produce a dark line along the gum margin, most often seen in children.
Extrinsic stain generally responds well to a professional clean, and to whitening where the underlying tooth colour is also to be lightened.
Intrinsic: colour within the tooth
This is colour in the dentine beneath the enamel, or in the enamel itself, and it cannot be polished off.
Ageing
Enamel thins over decades while dentine thickens and darkens. Teeth become gradually yellower. This is the most common intrinsic change and it generally responds reasonably to whitening.
A tooth that has had root canal treatment
Blood pigments from the pulp can discolour the dentine from within, producing a single grey or darkened tooth. External whitening has little effect. Internal bleaching, placing the whitening agent inside the tooth, is the technique used here, with a veneer or crown as the alternative.
Trauma
A knocked tooth can darken months or years later as the pulp responds or dies. A tooth that darkens after an injury should be assessed rather than simply covered.
Tetracycline
Tetracycline antibiotics taken while teeth were forming, or by the mother during pregnancy, bind into the tooth structure and produce grey or brown horizontal banding. This responds poorly to whitening. Veneers are usually the realistic route.
Fluorosis
Excess fluoride during tooth development produces white flecks or, in more marked cases, brown mottling. Mild cases can sometimes be improved with microabrasion or resin infiltration; more marked cases need veneers.
Decay and old restorations
Decay darkens the tooth from within. Old amalgam fillings can leave a grey cast in the surrounding tooth. Ageing composite fillings discolour at the margins. These need repair rather than whitening.
Working out which you have
Rough guide: stain that is heavier near the gum line and between the teeth, and that improves noticeably after a clean, is extrinsic. Uniform yellowing across all teeth suggests ageing. A single dark tooth suggests an internal cause in that tooth. Banding, mottling or white flecks suggest a developmental cause. Any of these is worth an examination rather than a guess, because the treatments diverge sharply.
What works for what
- Professional clean: removes extrinsic stain. Often the least costly meaningful improvement, and the sensible first step.
- Whitening: lightens the natural tooth structure, works most predictably on yellowish ageing discolouration, less well on grey.
- Internal bleaching: for a single root-treated tooth.
- Microabrasion or resin infiltration: for some white spot lesions and mild fluorosis.
- Composite bonding: masks localised discolouration conservatively. See composite bonding for small repairs.
- Veneers: for tetracycline staining, marked fluorosis or where shape is also to be changed. See porcelain or composite veneers.
One constant across all of it: crowns, veneers and fillings do not respond to whitening at all, so sequencing matters. See why whitening does not change crowns or veneers.
What it costs
Our new patient consultation and clean package starts from $219. Whitening packages start from $489, with take-home alone at $489, in-chair alone from $699, and a combined package at $998. Composite veneers start from $700 and handcrafted porcelain veneers from $1,490 per tooth. An examination first is what tells you which of these is actually relevant to your teeth. Current fees are on our price list, with more on teeth whitening.
Common questions
Why is only one of my teeth dark?
A single discoloured tooth usually points to an internal cause in that tooth, most often a non-vital pulp following trauma or root canal treatment. It should be examined.
Will whitening work on grey teeth?
Grey discolouration responds less predictably than yellow. An examination gives a realistic expectation before you spend anything.
Do whitening toothpastes change tooth colour?
They remove some surface stain by abrasion or mild chemical action. They do not change the underlying colour of the tooth, and abrasive formulations can wear enamel over time.
Can white spots be removed?
Sometimes, with microabrasion or resin infiltration, depending on the cause and depth. Others are better masked with bonding or veneers.
Booking an appointment in Canberra City
Civic Gentle Dental Care is a dentist in Canberra City at Suite 8, Level 3/161 London Circuit, a short walk from the Canberra Centre. To arrange an appointment, call (02) 6247 0224 or send us a message through our contact page.
This article is general information only and is not a substitute for individual dental advice. Whether a treatment is suitable for you, and what it will involve, can only be determined after an examination by a dentist. Any prices mentioned are estimates drawn from our current price guide and are not a quote.