Teeth whitening
Teeth whitening lightens discolouration that has penetrated the enamel and dentine using peroxide-based gels; the usual target is 2–6 shades on the VITA scale.
- Procedure time
- In-surgery 45–60 minutes · at home 10–14 days
- Anaesthesia
- Not needed
- Recovery
- No separate healing period; sensitivity possible for 48 hours
- Sessions
- In-surgery 1–2 sessions · at home a course
- How long it lasts
- 1–3 years; depends on diet and smoking
Two methods
In-surgery whitening uses a high-concentration gel applied under supervision with the gum isolated, and the result is visible in the same appointment. One session takes 45–60 minutes.
At-home whitening uses a custom tray and a low-concentration gel worn for a few hours a day. The result comes over 10–14 days and there is usually less sensitivity.
Cleaning first, then whitening
Whitening done over calculus and surface stains gives an uneven result, because the gel cannot contact the surface evenly. Professional cleaning therefore comes first.
Gel applied where there is decay or an open restoration margin reaches the dentine and markedly increases sensitivity. Those areas are treated before whitening.
Crowns and fillings do not whiten
Composite fillings, crowns and veneers are unaffected by whitening gel. Once the natural teeth lighten, a visible colour difference can appear between them.
If you have restorations or crowns in the front region, the possibility that they will need replacing to match the new shade is discussed before treatment and written into the plan — because that changes both the timescale and the scope of the trip.
What determines how long it lasts
Whitening lasts between 1 and 3 years, and what determines that is mostly daily habit: coffee, tea, red wine, dark soft drinks and smoking bring the colour back.
Short at-home maintenance courses under a dentist’s supervision can be used. The dentist sets the frequency; uncontrolled, frequent repetition can make sensitivity permanent.
- Avoid staining food and drink for the first 48 hours
- Smoking markedly shortens how long the result lasts
- Six-monthly professional cleaning delays surface staining
- Maintenance courses only on a dentist’s advice and at the stated frequency
Who this is not for, and what not to expect
Whitening works only on natural tooth tissue. Crowns, veneers and composite restorations do not lighten, so in a patient with many restorations at the front, whitening alone will not give a balanced result.
Not every discolouration lightens to the same degree. In structural discolouration from medicines such as tetracycline, and in fluorosis, the result is limited; veneers or composite masking are assessed for those cases.
- Crowns, veneers and composite restorations — they do not lighten and may need replacing
- Pregnancy and breastfeeding — elective whitening is deferred until after birth
- Untreated decay, cracked teeth and open restoration margins — treated first, as gel would reach the dentine
- Marked tooth sensitivity and exposed root surfaces — no course is started until the sensitivity is addressed
- Under 16–18 — enamel and pulp are still developing, so not done without a dentist’s assessment
This page is general information and does not replace a clinical examination. The method, dose and timescale that apply to you are decided by a doctor after examining you.
Frequently asked questions
Does whitening damage teeth?
How many shades will my teeth lighten?
How long does the whiteness last?
Will it be sensitive?
Pre-assessment
Describe your situation and we will answer with a measurement
Send a photograph or an X-ray. A doctor in the relevant speciality will reply with a graft range, a number of teeth or a dose range in units. If you are not suitable, we say so plainly.