Yellow teeth: causes and solutions that work, depending on the type of staining

Why teeth turn yellow: the short answer

Teeth turn yellow for two main reasons. Either pigments settle on the surface of the enamel (coffee, tea, tobacco, plaque and tartar): these are extrinsic stains, which often come off with a professional clean. Or the colour comes from inside the tooth (age, genetics, certain medications, trauma): these are intrinsic stains, which are better treated with whitening or, in some cases, veneers.

A tooth is never pure white. Its shade depends mainly on the dentine, which is naturally yellowish and lies beneath the enamel. Enamel itself is translucent: the thinner it is, the more the dentine shows through. That is why two people with the same oral hygiene can have teeth of very different shades.

Identifying the cause is therefore the first step. Using a whitening product on a stain it cannot treat wastes time and can sometimes damage the enamel.

Surface stains (extrinsic)

These are the most common. Pigments attach to the thin film that naturally coats the enamel and build up over time.

The main sources:

• coffee and tea (including strongly brewed mint tea), red wine, some soft drinks and highly coloured spices;
• tobacco in all its forms and shisha, which leave dark brown deposits, especially at the neck of the teeth and on their inner surfaces;
• plaque and tartar, which are porous, trap pigments and turn yellow to brown;
• some mouthwashes such as chlorhexidine, useful for a short period but able to stain with prolonged use;
• liquid iron supplements, which can leave dark marks, particularly in children.

These stains can usually be removed by scaling followed by polishing, or by air polishing. The result is often striking, but it does not change the tooth's own colour. If you smoke, our article on tobacco and oral health explains its other effects.

Internal discolouration (intrinsic)

Here the colour lies within the structure of the tooth, and cleaning does not change it.

• Age. Over the years, enamel thins through wear while dentine thickens and darkens slightly. Teeth naturally look more yellow, without this being a sign of disease.
• Genetics. Some people have thinner enamel or more saturated dentine from the moment their teeth come through.
• Acid erosion. Fizzy drinks, citrus juices, acid reflux or repeated vomiting dissolve enamel; the yellow dentine becomes more visible and the teeth often become sensitive.
• Certain medications taken in childhood, particularly tetracyclines, can leave grey, yellow or brown bands that are difficult to treat.
• Excess fluoride while the teeth are forming (fluorosis), which mostly causes white spots, sometimes brown ones.
• Trauma or a root-filled tooth. A single tooth that darkens towards grey or yellow-brown often points to a problem with the nerve and should be examined.

Some rare enamel or dentine disorders also exist and require a precise diagnosis.

What works, cause by cause

The solution follows directly from the diagnosis:

• Surface stains and tartar: a professional clean and polish, then prevention. This is often enough to restore the original shade.
• Yellowing due to age or genetics: this is the classic indication for teeth whitening. Hydrogen or carbamide peroxide penetrates the enamel and breaks down the pigments inside the tooth. It can be done in the chair or at home with custom-made trays, under the dentist's supervision.
• A root-filled tooth that has darkened: internal whitening, carried out from inside the tooth, may be considered once the root canal treatment has been checked.
• Tetracycline staining: whitening gives variable results and often takes time; veneers can be discussed if the outcome is not sufficient.
• Erosion: the acid source must be stopped first. Whitening is of little use here, while bonded restorations can protect the teeth and restore their colour.

Remember: crowns, veneers and fillings do not whiten. If you have them on visible teeth, they may need replacing after whitening so that they match.

Whitening toothpaste, charcoal, lemon: what you should know

Home remedies and over-the-counter products are tempting, but their effect is often misunderstood.

• "Whitening" toothpastes. Most work by gentle abrasion or with agents that lift surface stains. They can help maintain a result but do not change the internal colour. If too abrasive, they wear enamel over the long term.
• Activated charcoal. Its real whitening effect has not been demonstrated, and its abrasiveness can scratch enamel and irritate the gums.
• Bicarbonate of soda. Used occasionally, it removes some stains, but frequent, vigorous use is abrasive.
• Lemon, vinegar, rubbed strawberries. These are acids: they demineralise enamel and, paradoxically, can make teeth look more yellow over time by exposing the dentine.
• Whitening kits sold online. Their composition and strength are sometimes unknown, and one-size trays let the product leak onto the gums.

Our article on the risks and precautions of teeth whitening explains why effective whitening should follow an examination.

Keeping teeth lighter day to day

Once the shade has improved, a few habits help to keep it:

• brush twice a day with a fluoride toothpaste and clean between your teeth to limit the plaque that holds pigments;
• rinse your mouth with water after coffee or tea, and avoid sipping them for hours;
• use a straw for very coloured or acidic drinks;
• after an acidic drink, wait a little before brushing so as not to wear softened enamel;
• cut down on or stop tobacco, which remains one of the most stubborn causes of staining;
• plan regular check-ups and professional cleaning, at the interval your dentist recommends.

After whitening, the shade may relapse slightly over time, especially if habits do not change. A top-up session is sometimes suggested.

Having your yellow teeth assessed in Rabat

An examination answers the real question: is your discolouration on the surface, internal, or both? The dentist looks at how the colour is distributed (even, in bands, on a single tooth), checks for tartar, decay or signs of erosion, and assesses any existing restorations. An X-ray can be useful when one tooth on its own has changed colour.

At German Dental Clinic in Agdal, this assessment often begins with a scale and polish, which reveals the real shade of the teeth before whitening is discussed. The options are then explained to you along with their limits, with no promise of an identical result for everyone.

If you live in Rabat and the colour of your teeth bothers you, you can book an appointment to identify the cause and choose the solution that matches it.