Whitening the teeth, also called bleaching, is one of the most popular dental treatments in Germany. Done properly, occasional whitening is safe.
What to watch out for
Many important discoveries can be traced back to a simple accident. That is true of tooth whitening too. In the 1960s the American orthodontist Bill Klusmier used glyoxide to treat inflamed gums in his patients. To kill the bacteria they were expressly instructed to place the disinfectant in a tray and wear it all night. Since the antiseptic contains carbamide peroxide, which breaks down into the bleaching agent hydrogen peroxide, Klusmier noticed that after a while the teeth had become lighter. Klusmier is thus the inventor of one of the most popular whitening techniques: bleaching at home.
Most bleaching agents contain hydrogen peroxide
A beautiful smile is not only a modern ideal of beauty. Legend has it that the ancient Romans used urine as a method of whitening teeth. Before hydrogen peroxide became widespread in the twentieth century, other alternative agents such as nitric and citric acid were tried over the course of history. Most bleaching agents contain hydrogen peroxide: it breaks down the colour pigments by penetrating the top layer of the teeth. The American bleaching craze began in the early 1990s and spread to Germany shortly afterwards, says Christoph Benz, chair of the German Dental Association. Since then whitening has been one of the most popular dental treatments. The key to it is self-optimisation, according to Benz: bright teeth count as a sign of youth and vitality.
A tray can be used at night
Benz advises having the teeth professionally cleaned before whitening. That removes the plaque on the surface, which already makes the teeth whiter. Bleaching only comes into question if the effect is not sufficient for the patient. The fastest route is the in-office technique, in which a high-dose gel is applied at the practice and frequently heated with a special lamp for an even faster effect. That usually requires two to four sessions of about 30 minutes each. Alternatively the patient can have a tray fitted by their dentist and fill it with gel at night. This tray has to be worn daily for about two weeks, for an hour and a half to two hours. The bleaching solution is used in smaller amounts, which makes the process slower but gentler. That is the better choice for the teeth. Both methods can achieve a noticeable whitening effect lasting five years.
Avoid bleaching more than once a year
A dentist should carry out a complete examination before any bleaching. Hydrogen peroxide can penetrate the tooth and irritate the nerve if there is untreated decay or leaking crown margins. It should also be made clear to the patient that filling material does not bleach along with the tooth. Otherwise, says the dentist, correctly performed bleaching is safe, although the teeth can become temporarily more sensitive to heat and cold for a few days. The German Dental Association advises against bleaching several times a year, although there is no information about possible harmful long-term consequences. It is also important to treat freshly bleached teeth gently. For the first one to two weeks the enamel can be softer. If you use harsh abrasives on your teeth during that time, you risk damaging the enamel and letting the yellowish dentine show through, which makes further whitening necessary. The tooth gets darker and darker if you then scrape at it again, and you end up in something of a vicious circle.
Home remedies such as baking soda and lemon juice are inadvisable
What about bleaching kits, strips and pens sold in pharmacies and chemists? With over-the-counter products you can hardly go wrong, but you rarely achieve a result either. Over-the-counter solutions such as lemon juice and bicarbonate of soda are inadvisable, since the acids and abrasives they contain attack the enamel. Whitening toothpastes, on the other hand, often deliver what they promise. Stefan Zimmer, president of the German Society for Preventive Dentistry, explains that although they do not lighten the teeth, they can at least reduce discolouration. In the past the pastes usually used high doses of abrasives to achieve this effect, which can attack the enamel. It is, however, increasingly common to use abrasive and chemical ingredients together. Zimmer says these do not harm the teeth. Some pastes also contain the pigment blue covarine, which lightens the teeth temporarily. «This colour is not only safe for the teeth but also effective. You must not, of course, expect miracles», says Zimmer.
The costs are not covered by insurers
Only professional bleaching can produce lasting lightening. But that costs a few hundred euros and is generally not covered by health insurers. The desire for it changes with the seasons, incidentally: in summer the skin is darker and the teeth look lighter, which is why most patients come in winter.
Facts about tooth colour, enamel and cleaning
Discolouration
The colour of our teeth is determined by our DNA. Essentially our teeth darken with age, because the enamel erodes and the yellowish dentine beneath shows through more strongly. The proDente initiative explains that this is a normal process. Darkening can, however, also be a sign of another condition, for instance one affecting the nerve of the tooth. Occasionally certain medicines can also cause discolouration. In addition, the tooth appears darker because of extrinsic deposits: pigments from tea, coffee, tobacco, red wine, spices or fruit can remain on the surface.
Brushing
This can be avoided by brushing frequently and having the occasional professional cleaning. Pigments can, however, also become lodged in the enamel that covers the tooth, and are then harder to polish away. The perception of bright teeth is in theory very subjective; darker skin can have the same effect as a light lipstick. Since light is also reflected better by larger teeth, they appear brighter overall. To make restorations as inconspicuous as possible, dentists and technicians assess the colour of the teeth before an appointment using a shade guide.
