Tooth discoloration can be caused by various factors; internal, external or physiological - aging. Internal discoloration, incorporated into hard dental tissues, is the result of structural and metabolic changes, the use of drugs or as a result of trauma. External disolorations are limited to the tooth surface and are mainly related to bacterial plaque and chromogen consumption, and are divided into those caused by metal and nonmetal substances. Hydrogen and carbamide peroxide are used in various concentrations in vital teeth whitening therapy. The whitening mechanism is based on a redox reaction that cleaves the chromogenic macromolecules to smaller molecules that are not visible to the human eye. We can devide vital tooth bleaching techniques into in-office and at-home bleaching techniques. We use higher concentrations of peroxide in professional in-office techniques while using lower concentrations for at-home use. Materials that are used in in-office techniques can be activated with light, heat or with lasers or individually customised trays can be used for bleaching. There are also various commercially available teeth whitening products on the market. Prior to selecting a particular technique, anamnesis and clinical examination should be preformed as well as adequate preparation and protection of the patient. The bleaching technique is performed according to the manufacturer's instructions to avoid possible complications in the sense of hypersensitivity or soft tissue demage.