Diagnosis of the type of discolouration
We examine under good light, record the shade, test any single dark tooth for vitality and take X-rays where needed. Photographs show how much is surface stain versus intrinsic colour.
About this treatmentDental condition · Wimpole Street, Marylebone
Tooth discolouration and stains: surface, internal and single-tooth causes explained
Teeth are not naturally brilliant white. Enamel is translucent and the dentine beneath it is yellow, so the shade you see is a blend of the two, and it deepens with age as enamel thins. Against that background, discolouration falls into three groups that behave very differently. Stains sitting on the surface come from tea, coffee, red wine, curry and tobacco and lift with professional cleaning. Colour that has soaked into the tooth structure, from age, fluoride during childhood, certain antibiotics or years of surface staining, responds to whitening in most cases. A single tooth that has darkened on its own is a warning rather than a cosmetic issue, because it usually means the nerve inside has died or the tooth has been injured. Our Wimpole Street dentists identify which of these you have before recommending anything, since a treatment that suits one is useless or harmful for another.
Recognising it
How it usually feels
Yellow or brown film at the gumline and between teeth
Surface stain bound to plaque and tartar; removable by a hygienist.
Overall shade darker or yellower than it was ten years ago
Enamel thinning and dentine darkening with age; responds to whitening.
White, cream or brown flecks that have always been present
Fluorosis or a developmental enamel defect; whitening can even the shade but not remove them entirely.
Grey or blue-grey banding across several teeth
Tetracycline exposure during tooth formation; deep and stubborn to bleach.
One tooth that is grey, brown or pink compared with its neighbours
A non-vital tooth or internal resorption; needs testing and an X-ray.
A dark line at the edge of a crown or old filling
Metal showing through, a leaking margin or stain at the junction.
Behind the symptoms
What's going on
- 01
Diet and smoking
Tannins in tea, coffee and red wine, pigments in curry, berries and balsamic vinegar, and tar from tobacco bind to the protein film covering teeth and to any roughness or plaque. The stain builds gradually and is most visible on the front teeth and where brushing is weakest.
- 02
Age
Enamel wears thinner over decades, letting the yellow dentine show through, while the dentine itself lays down more layers and darkens. Everyone’s teeth become somewhat darker over time regardless of habits.
- 03
Developmental causes
Too much fluoride while the enamel was forming produces white flecks or brown mottling (fluorosis). Illness or fever in early childhood can leave a band of weaker, discoloured enamel. Tetracycline antibiotics given under the age of eight or in pregnancy deposit a grey-brown pigment in the developing dentine.
- 04
A dead or injured tooth
After a knock, or when decay kills the pulp, blood breakdown products seep into the dentine and the tooth darkens from within, often to grey. This can happen years after the original injury and is frequently painless. It signals infection risk rather than merely a colour problem.
- 05
Old restorations
Amalgam fillings can stain the surrounding dentine grey. Composite fillings absorb stain and become yellower than the tooth over years. Metal-based crowns can show a dark line as gums recede. These are corrected by replacing the restoration rather than by whitening.
- 06
Mouthwashes and medicines
Chlorhexidine mouthwash used for weeks stains teeth brown, particularly around the gumline. Iron supplements and some antihistamines and antipsychotics are also associated with staining. These stains are external and can be polished off.
Before your appointment
What you can do today
- Drink staining drinks through a straw or with meals rather than sipping over hours, and rinse with water afterwards.
- Wait thirty minutes after acidic food or drink before brushing so softened enamel is not scrubbed away.
- Use a fluoride toothpaste twice daily; whitening toothpastes remove surface stain only and can be abrasive if used aggressively.
- Clean between the teeth daily, since stain settles in the same neglected areas as plaque.
- Limit chlorhexidine mouthwash to short courses unless a dentist has advised otherwise.
- Avoid internet bleaching kits with unknown ingredients or acidic recipes such as lemon juice, which strip enamel.
These are holding measures, not a substitute for an examination. Use any pain relief exactly as directed on the pack and check with a pharmacist if you take other medicines.
In the chair
How we treat it at Wimpole Street
Hygiene and Airflow stain removal
Scaling removes tartar; Airflow polishing with fine powder lifts stain from enamel, between teeth and around restorations without abrasion. Many patients are surprised how much lighter their teeth look after cleaning alone.
About this treatmentProfessional teeth whitening
Custom trays and a dentist-prescribed carbamide peroxide gel, worn at home for two to three weeks, lighten intrinsic colour by several shades. Suited to age-related yellowing and mild fluorosis; less effective for grey tetracycline banding.
About this treatmentInternal whitening of a dead tooth
A single root-treated dark tooth can be bleached from the inside by placing gel in the crown of the tooth over a few visits, often avoiding a veneer or crown.
About this treatmentComposite bonding
Localised white or brown flecks, or a tooth that whitening has not evened out, can be masked with a thin layer of composite matched to the neighbours.
About this treatmentVeneers or crowns
For deep tetracycline staining or heavily restored teeth, porcelain veneers or crowns cover the colour reliably and are chosen once whitening has been considered first.
About this treatmentFees
Costs to expect
An examination at Wimpole Street to establish the cause of discolouration is expected to be £95. A hygiene visit is £89, or £142 with Airflow stain removal, and for surface staining this is often the only treatment needed. Home whitening with custom trays and professional gel is indicative at £399.
Internal bleaching of a single dark tooth is quoted after the tooth has been assessed and, where necessary, root treated (£695). Composite bonding to mask a fleck or even out one tooth is from £395. Porcelain veneers are indicative at £1,095 per tooth and composite veneers at £595. Whitening is done before any bonding or veneers so that the new material can be matched to the final shade.
Figures are indicative prices for Wimpole Street and are confirmed in a written plan once a dentist has examined you. Fees match our South Kensington and St Paul's clinics.
Don't wait if
When to see a dentist
- One tooth has darkened compared with its neighbours, with or without pain.
- A front tooth changed colour after an injury, however long ago.
- Staining is not shifting with brushing and you would like it professionally removed.
- You are considering whitening and want to know whether your discolouration will respond.
- A dark line has appeared around a crown or filling.
- Your teeth have developed new patches or a general colour change over a short period.
FAQ
Common questions
The likeliest explanation is that the nerve inside has died, often after an old knock, and pigment from the breakdown of blood has stained the dentine. It may not hurt, but the tooth can harbour infection, so it needs vitality testing and an X-ray. Treatment is root canal followed by internal whitening or a veneer.
It lightens the colour of the tooth itself and works well for yellow and mild brown discolouration. It does not remove surface stain, which is cleaned off beforehand, and it has limited effect on grey tetracycline bands, white fluorosis spots, fillings, crowns or veneers. We tell you in advance what to expect for your particular case.
Dentist-supervised whitening using regulated peroxide concentrations does not damage enamel structure. Temporary sensitivity is common for a few days. Unregulated products and acidic home remedies are a different matter and can erode enamel.
The natural tooth will lighten but the restorations will not, so a filling or crown that matched before may stand out afterwards. We plan whitening first and replace visible restorations to the new shade around two weeks later once the colour has stabilised.
They are cosmetic rather than damaging in themselves, but heavy stain indicates plaque that has been left in place, which does matter. Regular hygiene visits keep both under control.
These are usually mild fluorosis or a developmental defect in the enamel. Whitening often makes the surrounding tooth lighter so that the spots blend in, and resin infiltration or composite bonding can mask spots that remain. See our white spots page for detail.
Marylebone, W1
Wimpole Street opens 1 October 2026
Leave your details and we will be in touch when the Marylebone diary opens. If the problem cannot wait, the same clinicians are already seeing patients in South Kensington and at St Paul's.
Related conditions
Opening 1 October 2026
Wimpole Street is not yet seeing patients. Until then, please book or call our South Kensington clinic on 020 7183 2362 or our St Paul's clinic on 020 7183 3709. Questions about the new clinic: wimpolestreet@md.co.uk.
Until we open
Need an appointment before 1 October 2026?
The same clinical team already works from two other Medical & Dental clinics. Book at either one now and, if you prefer, move your ongoing care to Wimpole Street once the doors open.
South Kensington
- 20 Old Brompton Road, London SW7 3DL
- Open seven days a week
- 020 7183 2362
St Paul's, City of London
- 5 Ave Maria Lane, London EC4M 7AQ
- Open Monday to Friday
- 020 7183 3709
