Teeth Whitening

Where it may be suitable

• Healthy teeth that have darkened with age, or from tea, coffee or smoking
• Lightening the natural colour of the teeth first, when crowns, veneers or another cosmetic procedure are being considered

Where it is not suitable, or other treatment is needed first

• Under-18s. Under EU rules, whitening products are not used on anyone under 18 (see the product rules below).
• Pregnancy and breastfeeding. Whitening is postponed because there are not enough safety data.
• Untreated decay, gum disease or cracks. Whitening can make pain or irritation worse; these are treated first.
• Exposed root surfaces and marked sensitivity. Sensitivity may increase.
• Allergy to peroxide.

Where its effect is limited

• Fillings, laminate veneers and crowns. Their colour does not lighten. If you have restorations like these on your front teeth, they may need replacing after whitening so that the colours match.
• Discolouration caused by medicines. Dark discolouration caused by some medicines responds to whitening more slowly and to a limited degree; a longer course may be needed.
• A root-filled tooth that has darkened. It responds only partly to whitening from the outside. In suitable teeth, a separate procedure can whiten the tooth from the inside: the condition of the root filling is assessed and a protective barrier is placed inside the tooth. Rarely, this internal whitening has been followed by loss of tissue from the outer surface of the root near the gumline (external cervical resorption).

Whether whitening suits you is assessed at an examination, with X-rays where needed.

• Doing nothing, or a professional clean only. If the discolouration comes from surface staining, scaling and polishing may be enough.
• In-clinic whitening. The gums are protected and a high-concentration gel is applied to the teeth. The result starts to show the same day; the colour settles over a few days as the teeth regain their moisture.
• Home whitening. Trays are made to fit your teeth, and you apply a low-concentration gel at home for as long as your dentist tells you. The result appears gradually over several days.
• Both together. Whitening started in the clinic is continued at home with a low-concentration gel.

A review covering hundreds of clinical studies compared the two routes. Once a suitable programme has been completed, home and in-clinic whitening supervised by a dentist give a similar colour change on average¹; the number of sessions and the time needed vary from person to person. So the choice of method depends less on the result than on your time, how prone you are to sensitivity and what you prefer.

Light and laser

Routine use of light, LED or laser has not been shown to add a clear benefit² to whitening; the evidence on some specific protocols is limited, and some laser protocols can increase sensitivity.

Over-the-counter and dentist-only products

Under EU cosmetics law, products with up to 0.1% hydrogen peroxide are sold freely³. Products with more than 0.1% and up to 6% are sold only to dental practitioners. The first use of each course is carried out by a dental practitioner or under their supervision. These products are not used on anyone under 18. Products above 6% are not permitted as cosmetics. In Turkey, whitening products containing or releasing up to 6% hydrogen peroxide are classed as cosmetics⁴, not medical devices. The sales conditions above are EU rules; the Turkish announcement does not restate them.

Products on free sale contain very little peroxide. Highly abrasive products and hard brushing can increase wear, especially on exposed root surfaces; ask your dentist which toothpaste suits you.

An examination comes first; any decay, cracks or gum problems are treated before whitening. Your starting shade is recorded.

Risks and side effects

• Tooth sensitivity. This is the most common side effect. The risk is higher with some high-concentration products⁵; it also depends on the active ingredient, how long the gel is applied and the person. According to reviews, it usually passes within two to three days¹. Desensitising treatments containing potassium nitrate or fluoride reduce sensitivity² without reducing the whitening effect.
• Gum irritation. If the gel touches the gums, it can cause burning and white patches. That is why the gums are protected in the clinic; at home, putting too much gel in the tray also leads to overflow and irritation.
• Uneven colour. Fillings, laminate veneers and crowns do not whiten; a colour difference can appear between them and the natural teeth.
• Less change than expected. Not every tooth lightens to the same degree; the shade that will be reached cannot be predicted exactly in advance.
• Colour returning. The colour partly returns over time; the treatment may need repeating.

Benefits

• No tissue is removed from the tooth.
• It is far less invasive than irreversible procedures such as crowns.
• If the result is not enough, your dentist can still assess the other options.

In the first days after treatment, the teeth may be sensitive to hot and cold. Avoiding very hot and very cold food and drink, and using a desensitising toothpaste, helps during this time.

Keeping the colour in the long term

• Tea, coffee, red wine and smoking stain the teeth again over time; cutting down on them keeps the colour longer.
• Brush twice a day with a fluoride toothpaste, and clean between your teeth every day.
• Keep up regular check-ups and cleans.

The effect of whitening is not permanent. The colour partly returns over time; how long the effect lasts depends on the person, the method used and habits such as diet and smoking. Whether it needs repeating is assessed at check-ups.¹

During home whitening, if you have marked pain or a burning feeling in the gums, stop, take the tray out, rinse your mouth with water and talk to your dentist before starting again.

Contact your dentist if any of the following happens:

• Sensitivity that lasts more than a few days or keeps getting worse
• Throbbing toothache that starts on its own
• Burning, a sore or white patches on the gums that do not go away

Swallowing gel. If you swallow more than a trace of gel, or feel unwell after swallowing it, get medical advice without waiting and keep the product packaging with you.

Emergencies. Facial swelling, a fever or severe pain are not an expected result of whitening; see a dentist without waiting. If you have difficulty breathing or swallowing, go to an emergency department. The emergency number is 112.

Fees are not given on this page. The main factors that shape the plan are:

• The method chosen: in the clinic, at home, or both
• Treatment needed first: cleaning, fillings, gum treatment
• For home whitening, making the trays and the amount of gel
• Replacing fillings, crowns or veneers whose colour no longer matches after whitening

Ask for the plan in writing, including what it covers.