Bleaching of slightly discoloured teeth using a customised tooth tray (internal bleaching), which is worn at nights, has become very popular in recent years. Commercially available bleaching products are generally available as a gel and can be applied in the dental practice (in-office bleaching) or by the patient at home using customised trays (home bleaching). Treatment using customised tooth trays after professional tooth cleaning is effective in patients with diffuse discoloration. Nice teeth impart a feeling of confidence and attractiveness with the majority of people, so that there is considerable social pressure to whiten discoloured teeth cosmetically. An attractive tooth shade can also be achieved by bleaching yet without reducing the enamel structure. Affected patients are pleased to take advantage of this option.