From coffee to cabernet: tackling tough teeth stains

Tea, coffee and red wine are among life's better things, and they all stain teeth. So does time. Here is what actually causes discolouration, what removes it, and — the part most whitening pages leave out — what whitening cannot fix.

Two different kinds of stain

This distinction determines whether whitening will work for you, so it is worth understanding before you spend anything.

Extrinsic staining sits on the outside of the enamel. It comes from what passes over your teeth: tea, coffee, red wine, cola, soy sauce, curry, tobacco, and plaque left to accumulate. It responds well to a professional clean and to whitening.

Intrinsic staining is within the tooth. Causes include ageing (the enamel thins and the yellower dentine beneath shows through), trauma to a tooth, certain antibiotics such as tetracycline taken while teeth were forming, excess fluoride during development, and a tooth that has had root canal treatment.

Intrinsic staining responds less predictably. Tetracycline staining in particular often responds poorly to whitening, sometimes needing much longer treatment and sometimes not lifting satisfactorily at all — in which case veneers or crowns are the realistic options. Any page telling you whitening will simply fix tetracycline staining is overselling it.

Work out which one you have

What you see	Usually	What helps
Yellow-brown film, worse near the gumline and between teeth	Extrinsic — tea, coffee, plaque	A professional clean, then whitening
Dark lines in the grooves of back teeth	Extrinsic — food and drink in the fissures	A clean; sealants for prevention
Overall yellowing, gradual, both arches	Ageing — thinner enamel, darker dentine	Whitening works well
One tooth noticeably darker or grey	Trauma, or a root-treated tooth	Internal bleaching, or a crown or veneer
Chalky white patches, present since the teeth came through	Fluorosis, or enamel formation defects	Whitening evens the background; sometimes microabrasion or bonding
Grey or banded discolouration across many teeth	Tetracycline	Responds poorly. Usually veneers or crowns
Black or dark brown line along the gumline, often in children	Chromogenic ("black stain") bacteria	Removed by a clean; tends to return
Brown-black staining after a medicated mouthwash	Chlorhexidine staining	Stops the rinse; removed by a clean

What colour are teeth meant to be?

Not white. Natural enamel is translucent with a warm underlying tone, and healthy teeth range from light yellow through grey-white. The very white, very opaque look people bring in on their phones is usually porcelain, not whitened natural enamel.

Teeth are also not one colour across a tooth: the biting edge is more translucent and often slightly grey, and the neck near the gum is warmer. That variation is what makes teeth look real, and it is why a perfectly flat white shade reads as artificial even when nobody can say why.

A realistic whitening result is a few shades lighter than where you started, with that natural character kept. That is the target we work to.

What whitening will not change

Whitening does not lighten crowns, veneers, bridges or fillings. They stay the shade they were made. If you have a white filling on a front tooth and you whiten the teeth around it, that filling will end up looking darker than its neighbours and may need replacing to match — an additional cost worth knowing about before you start, not after.

Whitening also will not fix a tooth that is grey from an old root canal in the same way it lightens the rest; that usually needs a different technique or a different treatment altogether.

The single dark tooth

Common after a knock years earlier, or after root canal treatment. External whitening will not lift one tooth to match its neighbours, because the darkness is coming from inside.

The usual approach for a root-treated tooth is internal bleaching: a whitening agent is sealed inside the tooth and changed over one or more visits. It works well in many cases. Where it does not, or where the tooth is heavily filled, a crown or veneer is the alternative.

A tooth that darkens after an injury should be assessed rather than only whitened — the discolouration is often a sign the nerve has died, and that has its own consequences.

Your options

A professional clean first. Before whitening anything, surface stain, plaque and calculus need removing. Many people are pleasantly surprised by the shade after a scale and clean alone — and it is far cheaper than whitening. It is also the only way to know what colour your teeth actually are underneath.

Custom take-home kits. Impressions are taken and trays made to fit your teeth, which keeps the gel on the teeth and off the gums. You wear them for a set period each day over one to two weeks. Results build gradually, and the trays can be reused later for a top-up.

In-chair whitening. A stronger gel applied by a dental practitioner in a single visit, with your gums protected. Faster, and useful if you have an event coming up.

Both. In-chair for an immediate change, then trays to continue and maintain it.

Which suits you depends on your teeth, the type of staining and how quickly you want the result. That is a conversation at an examination, not a decision to make from a website.

If whitening is not the answer

Worth naming the alternatives honestly, because whitening is not always the right tool.

Air polishing or a thorough scale and clean, where the problem is purely surface stain
Replacing old, stained fillings on front teeth, which sometimes accounts for most of what you are seeing
Microabrasion for some superficial white or brown enamel marks
Composite bonding to mask a localised defect — reversible in a way veneers are not
Veneers or crowns, where staining is intrinsic and severe. A larger commitment: tooth structure is usually removed, and they will need replacing eventually. See veneers

Side effects, honestly

Sensitivity is common — short sharp twinges to cold, during treatment and for a day or two after. It is usually temporary. Gum irritation can occur if gel contacts the gums. Tell us if you get sensitivity; the strength or the wear time can often be adjusted. There is more detail on sensitivity after whitening.

Results vary between people and are not permanent. Depending on your diet and habits, expect to top up periodically.

Over-the-counter and salon whitening

In Australia, products containing more than 6% hydrogen peroxide (or 18% carbamide peroxide) may only be supplied or used by a registered dental practitioner. Supermarket products sit below that threshold, which is why they act slowly and modestly.

Be wary of non-dental whitening services and of DIY approaches — charcoal pastes and baking soda scrubs are abrasive and can wear enamel, which is permanent and eventually makes teeth look more yellow, since it exposes more dentine.

Other things sold as whitening that are not:

Oil pulling — no evidence of a shade change
Lemon juice, vinegar or bicarbonate rubs — acid and abrasion. The brief brightness is etched enamel
Activated charcoal — abrasive, usually fluoride-free
Whitening toothpastes — these remove surface stain and are fine for that. They cannot change the underlying shade, whatever the box says
Purple toothpaste and colour-correcting products — an optical effect on the surface that lasts hours, not a change in the tooth
Whitening "pens" bought online — unregulated strength, no tray, and no examination first

Whitening is also not recommended during pregnancy or breastfeeding, and untreated decay or gum disease needs treating first.

What stains most, and what to do about it

Habit	Staining	Practical fix
Coffee and black tea	High	Rinse with water after; drink in one sitting rather than over an hour
Red wine	High	Water alongside; cheese afterwards; do not brush immediately
Cola and dark soft drinks	High, plus erosion	Straw; rinse; limit
Curry, soy, balsamic, beetroot, berries	Moderate	Rinse after eating
Smoking and vaping	Very high, and tenacious	Nothing else on this list compares to stopping
Green tea	Moderate	Milder than black tea
Iron supplements, liquid	Can cause black staining	Straw, rinse, ask your pharmacist about alternatives
Chlorhexidine mouthwash	Brown staining with prolonged use	Use only for the period prescribed

A note on milk in tea and coffee: it does reduce staining somewhat, because the proteins bind the pigments. Not a licence, but true.

Keeping the result

Rinse with water after coffee, tea or wine; use a straw for iced drinks; wait about 30 minutes before brushing after anything acidic, since enamel is temporarily softened; and keep up your check-ups and cleans.

A realistic maintenance pattern for most people: a professional clean at your usual recall interval, and a night or two of tray wear every six to twelve months. Keep your trays somewhere you will find them — remaking them is the largest part of the cost of starting again.

Questions we are asked

How many shades will I get? It varies with the starting shade and the type of staining, which is why nobody honest gives you a number before looking. Yellow-toned teeth generally respond better than grey-toned ones.

Will it damage my enamel? Properly used whitening does not. Abrasive home remedies do.

Can I whiten with crowns or veneers on my front teeth? You can whiten the natural teeth, but the restorations will not change, and you may then want them replaced to match. Work this out before starting.

How long before an event should I whiten? Finish at least a week beforehand. That allows for sensitivity to settle and for the shade to stabilise, which it does slightly after treatment.

Are my teeth too sensitive to whiten? Usually not, with preparation. Tell us at the start.

Is in-chair whitening better than trays? Faster, not better. Trays used properly reach the same place and are easier to top up.

Can teenagers whiten? Generally not before 18, other than in specific circumstances under dental supervision.

Who provides this here

Victorian Dental Group is a general dental practice in Malvern East and holds no specialist registration. Whitening is provided by our dentists after an examination, which is also where we will tell you if whitening is unlikely to achieve what you are picturing — and what would.

Victorian Dental Group — 291 Wattletree Road, Malvern East VIC 3145 · (03) 9088 5808 · book online

General information only, not personal dental advice. Individual results vary. See our disclaimer.

What is the difference between surface stain and internal discolouration?

This is the distinction that determines what will actually work. Extrinsic stain sits on the outside of the tooth — from tea, coffee, red wine, cola and smoking — and much of it comes off with a professional clean, no whitening needed. Intrinsic discolouration is within the tooth itself, from ageing, tetracycline taken while the teeth were forming, fluorosis, trauma or a dead nerve, and a clean does nothing for it. An examination establishes which you have before anything is recommended.

What causes staining?

Diet, chiefly tea, coffee, red wine, cola and strongly coloured sauces. Smoking, which produces particularly tenacious surface stain. Plaque left on the teeth, which picks up colour readily. Age, as enamel thins and the darker dentine beneath shows through. And certain medications, notably tetracycline antibiotics taken during tooth development.

Will a clean be enough?

Often, and it is worth trying first because it costs less and removes nothing from the tooth. A professional scale and clean lifts surface stain and polishes the enamel, and for many people that alone makes a noticeable difference. Whitening is the next step if the underlying colour is still not what you want.

In-chair or take-home whitening?

Both are prescribed after an examination, and both reach broadly similar results — in-chair is faster, take-home is more gradual. In-chair uses a stronger gel with the gums protected and takes one appointment. Take-home uses custom-made trays and a lower-strength gel worn over one to two weeks, and the trays are useful afterwards for topping up. Neither is inherently superior; they suit different people.

Does whitening work on every kind of stain?

No. It works best on yellowing from age, food and drink. Grey discolouration and tetracycline staining respond poorly and sometimes barely at all. White spots from fluorosis can become more noticeable rather than less. A single dark tooth that has had root canal treatment is a different problem needing a different approach. Where whitening will not deliver much, you should be told that rather than sold it.

What about my fillings and crowns?

They do not whiten. Composite fillings, crowns, bridges and veneers keep their existing colour, so after whitening they may no longer match the surrounding teeth and might need replacing to blend in — a real extra cost to factor in before you start, particularly with restorations on front teeth.

What are the side effects, and what should I expect?

Sensitivity to cold during and for a day or two afterwards is common and usually temporary; gum irritation can occur where gel contacts the gum. Results vary between people and no particular shade can be promised. Colour fades over time, faster with tea, coffee, red wine and smoking, so most people top up periodically. Whitening is not recommended in pregnancy or breastfeeding, or for children.

How do I keep stains off?

Rinse with water after staining drinks, use a straw for cold ones, and clean thoroughly twice a day so plaque does not pick up colour. Stopping smoking makes the largest single difference. Avoid the temptation to scrub with abrasive or charcoal pastes, which wear enamel and eventually make teeth look yellower. Start with a check-up and clean: Victorian Dental Group, 291 Wattletree Road, Malvern East VIC 3145 — (03) 9088 5808, Monday to Friday 8:00am to 5:00pm.