Tooth bleaching is a commonly practiced cosmetic procedure for teeth whitening and is derived from the English word "to bleach" (bleach) for bleaching. The reasons for changing the color of the teeth are varied. Decisive factors may be both externally acting - as for example nicotine, foods and beverages, and medical interventions, medicines, as well as for example if the tooth is with a treated root canal.

There are different ways of application for bleaching:

Тhe so-called "At-home whitening", wherein the patient carries an individually manufactured plastic dental splint in which a bleaching gel containing peroxide is placed.
Тhe so-called "In-office whitening" or "strong bleaching" is done exclusively and only in a dentist's office. A much higher concentration of peroxide is used in the bleaching agent and it is applied directly on the teeth to be bleached.
Whitening of non-vital teeth. For this purpose, the peroxide is introduced, for example into the root canal after opening of the tooth crown.