The Professional Whitening Guide
How it works, what it can and cannot do, and what to expect — before you book anything.
Please note
This guide is for general information only and does not constitute clinical or dental advice. Suitability for any treatment must be assessed by a qualified dental professional. Individual results vary.
How professional whitening works
Professional teeth whitening uses a peroxide-based gel applied to the teeth. The active ingredient penetrates the tooth enamel and breaks down the molecules responsible for discolouration. The result is a lightening of the natural tooth colour.
Professional whitening uses higher concentrations of the active ingredient than over-the-counter products and is carried out under dental supervision. Only registered dental professionals are legally permitted to supply whitening products containing more than 0.1% hydrogen peroxide in the UK.
Whitening works on natural tooth enamel. It does not change the colour of existing crowns, veneers, bridges, or fillings — something to consider if you have visible restorations.
Am I suitable for whitening?
A brief clinical assessment is needed to confirm suitability. Common factors a clinician will consider include:
Gum health
Active gum disease or significant recession should be addressed before whitening. Your clinician will advise.
Tooth sensitivity
Whitening can increase sensitivity temporarily. Dentinal hypersensitivity does not automatically rule out whitening, but the approach may need to be adjusted.
Existing restorations
Crowns, veneers, and tooth-coloured fillings on visible teeth will not whiten. Your clinician will advise whether this affects the suitability of whitening for you.
Pregnancy
Whitening is not recommended during pregnancy as a precautionary measure.
Types of staining — and what whitening can do
Not all discolouration responds equally to whitening. Understanding this is important for setting realistic expectations.
Extrinsic (surface) staining — Generally responsive
Caused by food, drink, and tobacco — coffee, tea, red wine, and smoking are common culprits. This type of staining generally responds well to professional whitening.
Intrinsic discolouration — Limited response
Discolouration within the tooth structure itself, caused by factors such as certain medications (e.g. tetracycline taken in childhood), developmental conditions, or trauma. Whitening has limited effect on intrinsic discolouration. A clinician may suggest alternative cosmetic options such as veneers or bonding.
Age-related darkening — Generally responsive
Teeth naturally darken with age as enamel thins and the underlying dentine shows through. This often responds to whitening, though results vary by individual.
Home trays vs in-surgery whitening
Your clinician will advise which approach is most appropriate for your situation and the result you are looking for.
Home whitening (take-home trays)
Custom-fitted trays are made from impressions of your teeth. You apply a whitening gel and wear the trays for a period specified by your clinician — typically one to two hours per day, or overnight, for two weeks or more. Gradual, controllable result. Can top up at home when trays are supplied. Requires commitment over several weeks.
In-surgery whitening
A higher-concentration gel is applied in the surgery, often with a light-activation stage. The appointment typically takes one to two hours. Faster visible result. Suitable if you prefer a single appointment. May be combined with home trays for best outcome.
Sensitivity during whitening
Temporary tooth sensitivity is a common side effect of whitening. It typically resolves within a few days of completing treatment. For patients who already experience sensitivity, the clinician may recommend a desensitising approach, a lower-concentration gel, or a more gradual protocol.
Sensitivity does not automatically rule out whitening, but it is important to discuss it at your consultation so the approach can be tailored appropriately.
How long do results last?
Whitening is not permanent. How long results last depends on your diet, lifestyle, and individual tooth chemistry. In general, the factors that originally caused staining — coffee, tea, red wine, tobacco — will cause it to recur over time.
Periodic top-up whitening with home trays can help maintain results. Your clinician will advise on a realistic maintenance approach for your situation.
Questions to ask at your consultation
Will my staining respond well?
Is my type of discolouration likely to respond well to whitening?
Do I need treatment first?
Do I need any gum or other treatment before whitening?
Will existing restorations be affected?
Will my existing restorations be affected, and will they need to be replaced?
Which method is best for me?
Which method — home trays or in-surgery — do you recommend for my situation?
What result is realistic?
What result is realistic for my tooth type?
How do I manage sensitivity?
How should I manage sensitivity if it occurs?
How long will results last?
How long should results last, and how do I maintain them?
Are there alternative options?
Are there alternative or complementary cosmetic options if whitening has limitations for me?