Before you whiten your teeth: what to do two weeks beforehand

The date for whitening usually comes from the calendar: a wedding, a photo shoot, a reunion. The date is fixed, so you call and ask for the nearest free chair. Yet how the colour turns out and how you cope with the treatment are largely decided in the two weeks before it. They hold two other visits, a few decisions with the dentist and some shopping that cannot be made up on the day of whitening.

Two weeks is not a buffer, it is an order

In-office whitening itself fits into one visit and takes 60 minutes. Before it, however, there are two separate appointments that cannot be combined with the treatment or with each other: a consultation with a check-up, and a hygiene visit. On top of that comes time for treating whatever the check-up finds. Hence two weeks: not a safety margin, but the real time needed to put the visits in an order that makes sense.

1. About 14 days before: a consultation and check-up (30–45 minutes). The dentist assesses whether you can have the treatment and says what needs doing first.
2. If the dentist recommends a toothpaste for sensitive teeth, you start using it straight after the consultation and stay with it until the treatment.
3. In the meantime: treating decay and replacing leaking fillings, if the check-up found them.
4. A few days before the treatment: a hygiene visit (45–60 minutes), as a separate appointment.
5. Treatment day: whitening, 60 minutes, one arch or both.
6. A few days after: assessing the shade that remains. Replacing fillings in the smile zone is planned later, after about two weeks.

Healthy teeth first, colour second

Whitening gel does not stay on the surface: it penetrates the enamel and dentine, because that is where the pigments to be broken down sit. If on the way it meets a cavity, a gap at an old filling or an exposed tooth neck, it gets a shortcut deep into the tooth. That is the source of the pain your friends talk about, and why the rule is that the assessment is an examination, not a formality.

It is worth coming to the check-up with a direct question: what stands in the way for me? The list of things that need treating or assessing before whitening is short and repeatable.

• Decay, even small and painless
• Leaking fillings, especially at the margin with the tooth
• Gum inflammation, bleeding when brushing, a receding gum line
• Exposed tooth necks and cervical defects
• Enamel cracks and teeth after an injury: they need a separate assessment before the treatment

Separately, there are contraindications that preparation cannot get around: whitening is not carried out during pregnancy or breastfeeding, or before the age of 18. It is worth knowing this before booking, not in the chair.

A hygiene visit before, not after

Tartar and stains have their own colour, and they account for part of the shade that bothers you. Gel placed on such a surface works unevenly: where the enamel is exposed it lightens, and where deposits cover it, much less. The result can be an uneven colour and the impression that the treatment “didn’t work”.

That is why we book the hygiene visit as a separate appointment a few days earlier: scaling, air polishing, polishing and fluoride take 45–60 minutes and are carried out by a dental hygienist. It has one more advantage: after cleaning you can see the true shade of the enamel. Sometimes it turns out to be enough, and the decision about whitening can wait.

“Part of the colour you want to change is deposits,
not the tooth. Only after a hygiene visit can you see
how much work is left for the gel.”

A principle we repeat at every consultation

Does whitening damage enamel?

This question comes up in the practice regularly, so it is worth separating two things. Whitening does not involve removing a layer of the tooth. The product breaks down pigment molecules accumulated in the enamel and dentine: what is in the tissue changes, not its thickness. Abrasion is a completely different mechanism, and it is exactly what home remedies with baking soda, charcoal or highly abrasive toothpastes rely on: they remove stains together with the top layer of enamel.

During the treatment itself and for a few days afterwards the enamel is temporarily dehydrated, which is why straight after the visit the teeth look lighter than they will in the end; the final shade is assessed after a few days, once the enamel has rehydrated. During that time it also absorbs pigments more easily, which is where the dietary restrictions come from. In-office strength gel, meanwhile, works at the chair, with the gums protected and under the eye of a dentist who adjusts the number and length of applications as they go, asking how you feel.

Sensitivity: what you can do beforehand

Sensitivity to cold is the most common reaction after whitening. It usually passes within 1–3 days and is often strongest on the first day. It cannot be ruled out in advance, but a few things are worth sorting out earlier than the day before the treatment.

• Ask at the consultation about a toothpaste for sensitive teeth: if the dentist recommends one, it makes sense to start two weeks before the treatment, not the day after it
• Stop using abrasive whitening toothpastes for that time
• Tell the dentist before starting if your teeth already react to cold; the application time and number of cycles can then be reduced
• Ask about whitening with custom trays if the sensitivity is marked: the colour then changes gradually, over a dozen or so days
• Do not plan the treatment for the day before the event; leave yourself a few days’ margin

Fillings, veneers and crowns will keep their colour

Gel lightens only the tooth’s own tissue. Composite and ceramics do not react to it at all. This is information that can turn the order of your plans upside down: a filling in a front tooth, invisible today, may start to stand out in a darker tone from the rest after whitening.

The conclusion is simple and applies to anyone thinking about restorations in the smile zone. First the target colour of your own teeth is set, then the material is matched to it, not the other way round.

• Planning bonding, flow injection or veneers: whitening goes first
• Have fillings in your front teeth: expect to replace them after the treatment
• Replacement and shade matching are planned after about two weeks, once the colour has settled
• Have crowns or veneers that are staying: mention it at the consultation, because they set the limit of lightening

Prepare the white diet before the treatment

For the first 48 hours after whitening the enamel absorbs pigments particularly easily, so that is when the restrictions are strictest. This can be planned: do the shopping beforehand and put together a menu without dark foods for those days. It is easier then than after the treatment, in front of an open fridge.

• Off the menu for 48 hours: coffee, tea, red wine and cola
• Foods: beetroot, soy sauce, curry, berries and tomato sauces
• Switch your mouthwash to a version without colourings
• Cigarettes and other tobacco products reverse the shade you achieved fastest
• Keep a toothpaste for sensitive teeth at home: it is often most helpful on the first day

After that there are no strict bans, but the same foods decide how long the colour lasts. The durability of the result is individual and depends on diet, hygiene and smoking. The degree of lightening is individual too: discolouration after an injury, after root canal treatment or after tetracyclines responds to gel less well than coffee stains.