Teeth Whitening: Methods, How Long It Lasts and What to Know

Tea, coffee, smoking and age all darken teeth over time, so teeth whitening is one of the most popular cosmetic dental treatments.

For general information only; your dentist decides the right method after an examination.

Why do teeth change colour?

External stains come from coffee, tea, wine and tobacco and can partly be removed by professional cleaning. Internal discolouration comes from within the tooth – ageing, some medications or trauma – and responds to whitening to varying degrees.

How it works

Gels containing hydrogen or carbamide peroxide break down colour pigments in the enamel. Done correctly, whitening does not thin or damage the tooth.

Methods

In-office whitening: the gums are protected and a stronger gel is applied, sometimes light-activated. About 1–1.5 hours, with immediate results; temporary sensitivity may be more noticeable.

At-home whitening: custom trays made by your dentist, used with a milder gel for 1–3 weeks. More gradual, and trays can be reused for touch-ups.

Combined: an in-office start followed by home treatment.

Over-the-counter products have limited effect and overuse can cause sensitivity; ask your dentist first.

Who is it for?

• Decay and gum disease should be treated first.
• Fillings, crowns and implants do not whiten and may need replacing to match.
• Usually not recommended during pregnancy or breastfeeding.

How long does it last?

Typically 1–3 years, depending mostly on habits. Regular cleaning and short touch-ups help maintain results.

Aftercare: the "white diet"

For 48 hours avoid tea, coffee, cola, red wine, dark sauces and smoking. Choose water, milk, yoghurt, chicken, rice and white cheese. Use a sensitivity toothpaste if advised.

The key step is an examination and a frank conversation with your dentist about expectations. Compare dentists near you and book online.