Bleaching

Bleaching is a method used to lighten teeth for cosmetic reasons. Tooth discoloration differs from plaque in that the coloring substances are stored in the enamel and dentin below the tooth surface and cannot be removed during professional tooth cleaning. Although professional tooth cleaning cannot remove these “internal” discolorations, professional tooth cleaning should be carried out before bleaching so that the tooth color can be better assessed and the whitening substances can take effect more effectively. The teeth should also be examined for tooth and gum damage before treatment.

Causes of tooth discoloration

Tooth discoloration is usually caused by coloring foods and beverages, such as alcoholic drinks, tea, tobacco, coffee, red wine, iced tea, etc. These initially accumulate on the teeth, but can also penetrate the tooth structures. They can also be caused by the effects of medication or as a result of accidents, tooth decay, death of the dental pulp or malnutrition. However, there are also age-related discolorations. The layer of yellowish dentin underneath the transparent enamel increases in size over the years as the nerve gradually recedes. As this yellowish dentin shines through more and more, the teeth become more yellow over the years.

Methods

The main component of whitening preparations is hydrogen peroxide (H2O2). These penetrate the tooth and split off oxygen radicals. These are able to chemically change the colorants in the tooth so that they no longer appear in color. In addition, the crystal structure of the enamel layer is changed so that it becomes more opaque and the dentin layer no longer shows through. In home bleaching, impressions of the teeth are taken and trays are produced in the laboratory. To whiten the teeth, these trays are filled with gel containing peroxide and, depending on requirements and the product, are worn for several hours, possibly over several days, until the desired whitening result is achieved. In-office whitening uses more concentrated preparations and the whitening is carried out directly in the dental practice. The gums are protected with a special rubber-like coating. The whitening material is applied directly to the teeth and intensified with bleaching lamps. The procedure can be repeated several times. If only a single devitalized tooth shows discolouration, the walking bleaching technique can be used, in which the bleaching material is inserted into the tooth.

Durability of tooth whitening

It cannot be guaranteed in advance how long the whitening effect of the teeth will last. The result usually remains stable for several years.

Side effects

Teeth sensitivity may occur after whitening, especially to sweet and sour foods and temperature. These symptoms usually subside after a few days. During the bleaching treatment, the color pigments in the tooth enamel are changed by chemical oxidation, which causes the whitening. It is conceivable that the teeth become rougher, more brittle or more susceptible to caries as a result, although no study has yet been able to prove this. The teeth are also deprived of minerals, which can lead to demineralization and a breakdown of the protein pellicles. This can lead to white spots on the teeth, although this usually returns to normal in the days following treatment.

Preparations on the open market

The preparations that you can buy over the counter are often insufficiently effective. Some of them are harmful to the teeth or lead to insufficient or uneven whitening. In addition, the dentist should always check whether bleaching treatment is advisable before it is carried out. Plastic fillings on the front teeth, for example, may become visible after the treatment.