Teeth whitening options in Braintree, and what each one actually does

There are three routes to whiter teeth and only one of them reliably works. Dentist-supplied home whitening with custom trays changes your shade by several steps over two to three weeks. Shop-bought kits are legally capped at a strength too weak to do much. Salon whitening by anyone who is not a dental professional is illegal in the UK.

That is the short version. Here is why.

Why shop-bought kits do so little

The active ingredient in whitening is hydrogen peroxide, or carbamide peroxide which breaks down into it. Products sold direct to the public in the UK are limited by law to 0.1% hydrogen peroxide. A dentist can prescribe up to 6% after examining you.

That is a sixtyfold difference, and it is the entire reason the strips you can buy in a pharmacy leave you thinking whitening does not work on your teeth. It is not your teeth.

You will also see kits sold with figures like “36% carbamide peroxide” from overseas sellers. Carbamide peroxide is roughly a third as strong as the equivalent hydrogen peroxide figure, so that is around 12%, which is double what I am allowed to prescribe. Unsupervised, at that strength, on unexamined teeth, is how people end up with chemical burns to the gums.

Why the trays matter as much as the gel

Custom trays are made from an impression or a scan of your own teeth. They hold the gel against the enamel and keep it off your gums. That does two things: the gel works where it should, and it does not burn where it should not.

Boil-and-bite trays do neither reliably. Gel squeezes out along the gum line, which is uncomfortable, and the coverage across each tooth is uneven, which is how you end up with patchy results.

What it costs

Dentist-supervised home whitening in the UK generally runs between £250 and £450 for both arches in 2026, including the examination, the trays and a full course of gel. In-chair systems cost more and, in my experience, do not finish meaningfully whiter than a properly run home course.

My own fees are on the teeth whitening page. The trays are yours to keep, which is the part that makes whitening cheap over time: a top-up later costs the price of a gel syringe rather than a whole new course.

Anything advertised at £99 is either a single-arch offer, or not dentist-supervised whitening.

How long the result lasts

One to three years, and the variable is you rather than the gel. Coffee, tea, red wine, curry and tobacco pull the shade back fastest, in roughly that order of how often I see it.

Most people notice the drift at around eighteen months. Two or three nights of top-up gel resets it. Done that way, one course of whitening plus an occasional syringe holds the result more or less indefinitely.

The first 48 hours after a course matter most. Enamel is temporarily more porous, so staying off deeply coloured food and drink for two days protects what you have just paid for.

What whitening will not touch

This is the part that gets glossed over in most whitening advertising.

• Crowns, veneers, bridges and composite bonding. Whitening only lightens natural enamel. Anything artificial keeps the shade it was made in. If you have a white crown on a front tooth and you whiten the teeth around it, you can end up with a worse match than you started with.
• Tetracycline staining and deep white patches. These respond partially at best. They usually need bonding or veneers, and I would rather tell you that than sell you a course that cannot work.
• Grey teeth after root canal treatment. A single dark tooth sometimes responds to internal whitening, which is a different treatment done from inside the tooth.

If you are planning both whitening and bonding or veneers, whiten first, then match the restorations to your new lighter shade. Doing it the other way round means the new work looks dark within weeks.

Why an examination comes first

Because whitening gel reaching exposed dentine through a crack, or sitting over an untreated cavity, genuinely hurts. Inflamed gums make it worse. Ten minutes of looking rules that out, and it is the reason supervised whitening can safely use strengths that shop-bought kits are not allowed to.

If you have not had a check-up in a while, that comes first regardless of whether you go ahead with whitening.

A note on who is allowed to do this

Tooth whitening is the practice of dentistry in UK law. It can only be carried out by a registered dental professional, or by someone working to a dentist’s prescription. Beauty salons and mobile “whitening technicians” offering it without a dentist are breaking the law, and the General Dental Council prosecutes for it.

If anyone offers you whitening, ask for the treating clinician’s GDC number. Mine is 76806 and you can look it up on the register.