Question 1

In-practice or at-home whitening: what is the difference?

Accepted Answer

At the practice, the dentist applies the product in one or a few sessions. At home, you wear custom-made trays with a prescribed gel over a longer period. The two can be combined. In-practice whitening uses a more concentrated gel, applied by the dentist after the gums have been protected. It gives visible lightening in a short time, generally in one or two sessions depending on the starting shade and the result you are looking for. At-home whitening relies on trays custom-made from impressions of your teeth. You place a less concentrated gel in them and wear them at the pace indicated, often for one to a few weeks. The result is gradual and often well tolerated. The two methods can be combined: a session at the practice to start the lightening, then trays at home to refine it or to maintain it later. Products sold over the counter, outside dental supervision, should be approached with caution. Before any whitening, an examination checks that there are no cavities or gum problems, and the dentist tells you which method suits you.

Question 2

Does whitening make teeth sensitive?

Accepted Answer

Temporary sensitivity to cold is possible during treatment and for a few days afterwards. It generally fades on its own and can be reduced with suitable products. The whitening gel passes through the enamel to act on the pigments inside the tooth. This can cause temporary sensitivity, especially to cold, or brief, sharp twinges. This sensitivity varies a great deal from one person to another. It is often more marked in people who already have sensitive teeth, exposed tooth necks or cracks in the enamel. Several measures help reduce it: using a toothpaste for sensitive teeth for a few days before and during treatment, spacing out home sessions or shortening the wearing time, and avoiding very cold drinks during this period. If the sensitivity becomes bothersome, do not hesitate to tell the dentist. The routine can be adjusted, a desensitising product applied or the treatment paused.

Question 3

Does whitening damage the enamel?

Accepted Answer

Carried out with suitable products and under a dentist’s supervision, whitening does not wear away the enamel. The risks come mainly from products used incorrectly or from overuse. Whitening does not scrape the surface of the teeth: it works through a chemical reaction that breaks down the pigments responsible for the discoloration. Used within a supervised routine, it does not cause any loss of enamel. Problems tend to arise with unsuitable products, poorly controlled concentrations or treatments repeated too often. Abrasive powders and pastes that claim to whiten can, on the other hand, wear the enamel with repeated use. An examination beforehand is important. A cavity, a crack or inflamed gums must be treated first, as the product could irritate the tooth or the gum. The dentist also checks that the cause of the discoloration is one that whitening can address. Some discolorations, for example those linked to certain medicines taken in childhood, respond less well. In that case, the dentist explains the results you can realistically expect and the other possible solutions.

Question 4

How long does the result of whitening last?

Accepted Answer

The result generally lasts from several months to a few years, depending on your habits. Coffee, tea, smoking and some strongly coloured foods speed up the return of staining. After whitening, the teeth gradually regain part of their original shade, at a pace that depends greatly on your lifestyle. There is therefore no fixed duration, and the result cannot be considered permanent. Smoking, tea, coffee, certain spices and coloured fizzy drinks are the main causes of restaining. Limiting them, or rinsing your mouth after having them, helps preserve the brightness you have achieved. Good daily hygiene and regular scaling remove surface stains and prolong the effect of whitening. If you have custom-made trays, the dentist may suggest short top-up sessions at home from time to time, and will tell you a reasonable frequency so that the treatment is not overused.

Question 5

Should I have whitening before veneers or crowns?

Accepted Answer

Often yes, if the remaining teeth need to match the new ones. Whitening has no effect on ceramic or composite, so it is done before their shade is chosen. Whitening products lighten natural enamel, but not restorative materials such as ceramic, the composite of veneers or old fillings. A crown fitted today will keep its shade, even if you whiten your teeth later. When only a few teeth are going to receive veneers or crowns, it is therefore often sensible to whiten the other teeth first. The shade of the new restorations is then chosen to match this new smile. After whitening, it is usual to wait a little, often one to two weeks, before choosing the final shade and bonding, while the colour settles. If you already have visible crowns or fillings, the dentist will point out that they may look darker after whitening and may need replacing to keep a harmonious result.

Teeth whitening

Teeth whitening

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