Coffee, tea, certain foods, and simply getting older can all affect the colour of your teeth.

But while some stains can be removed with a professional cleaning, others have causes that brushing alone will not fix.

Before spending money on whitening products, it helps to understand why teeth change colour and which treatments are safe.

Why do teeth become yellow?

Tooth discolouration generally falls into two categories: surface stains and changes that occur inside the tooth.

Surface stains

Surface stains develop when pigments from food, drinks, and tobacco collect on the enamel, the hard outer layer of the tooth.

Coffee, tea, red wine, and richly coloured foods can all contribute.

Plaque and tartar can also make teeth look yellow or brown, particularly around the gumline.

Brushing and flossing help prevent plaque build-up, but hardened tartar needs to be removed by a dental professional.

Deeper discolouration

Deeper discolouration occurs beneath the enamel and may be harder to treat.

Teeth naturally become darker with age as enamel wears down and the yellowish dentin underneath becomes more visible.

Other causes include dental injuries, certain medications taken while teeth are developing and excessive fluoride exposure during childhood.

A tooth that suddenly turns grey or dark, particularly after an injury, should be examined by a dentist.

White spots or dark patches may also need attention, as discolouration can sometimes indicate changes in enamel or tooth decay.

Which foods and drinks stain teeth?

You do not need to give up your morning coffee or favourite curry to protect your teeth, but it helps to be aware of what contributes to staining.

Common culprits include:

• Coffee and tea: Their pigments can gradually stain enamel.
• Red wine: Its colour compounds can leave surface stains, while its acidity can contribute to enamel erosion.
• Dark sauces and curries: Soy sauce, tomato-based sauces and turmeric-rich dishes can contribute to staining.
• Berries and beetroot: Their strong natural pigments may leave temporary surface marks.
• Tobacco: Smoking and other tobacco use can cause persistent yellow and brown stains.
  
  

Acidic drinks, including soft drinks and some fruit juices, can also weaken enamel over time.

As enamel wears away, the naturally yellow dentin underneath becomes more visible.

How to prevent tooth stains

Small changes to your daily routine can help reduce staining and protect your enamel.

• Rinse with water: Drinking or rinsing with water after coffee, tea or strongly coloured foods helps clear away residue.
• Brush and floss regularly: Good oral hygiene helps prevent plaque build-up. Use a fluoride toothpaste and a soft-bristled toothbrush.
• Wait before brushing after acidic foods: Citrus fruits, wine and soft drinks can temporarily soften enamel. Rinse with water and wait about 30 to 60 minutes before brushing.
• Keep up with dental check-ups: Professional cleaning removes hardened tartar that cannot be brushed away at home.
• Consider your habits: Cutting down on tobacco and frequently sipping acidic drinks can benefit both your teeth and your overall oral health.
  
  

What is the safest way to whiten teeth?

The right treatment depends on what is causing the discolouration.

Professional cleaning can remove plaque, tartar and many surface stains, although it will not change the natural colour of the tooth.

Whitening treatments use bleaching ingredients such as hydrogen peroxide or carbamide peroxide to lighten tooth colour. A dentist can advise whether professional treatment or a suitable take-home product is appropriate.

Whitening does not work equally well on every type of discolouration.

Deep stains, dental injuries and changes caused by certain medications may require other treatments.

Existing fillings, crowns and veneers will not whiten in the same way as natural teeth.

For some people, a dentist may recommend bonding or veneers to improve the appearance of stubborn discolouration.

These options have different costs, benefits and drawbacks, so it is worth discussing alternatives before committing to treatment.

Be careful with DIY whitening

Not every popular whitening hack is safe for your teeth.

Charcoal powders, lemon juice and other acidic home remedies can damage enamel or irritate gums. Once enamel has been lost, it does not grow back.

Whitening products can also cause temporary tooth sensitivity or gum irritation, particularly when used incorrectly.

Follow product instructions and speak to a dentist if you have sensitive teeth, untreated cavities or gum problems.

When should you see a dentist?

Gradually developing yellowing is often linked to ageing or surface stains, but a change in colour should not automatically be dismissed as cosmetic.

Make an appointment if one tooth becomes noticeably darker, discolouration appears suddenly, or you notice white or brown patches, pain or sensitivity. These changes may need treatment rather than whitening.

The goal is not necessarily to have perfectly white teeth.

It is to understand what is causing the discolouration and choose an approach that protects your teeth while addressing your concerns.