Figure 2. Non-vital tooth bleaching of a discolored tooth in a 21-year-old woman. The tooth had been endodontically treated 6 yrs earlier due to trauma. A slight discoloration, which subsequently became more intense, was visible immediately after the endodontic treatment. (A) Tooth #11 with a dark blue discoloration. (B) The result after 3 wks of internal bleaching with sodium perborate suspended in water and a weekly change of bleaching agent. (C) 5 yrs after internal bleaching. Only slight discoloration is visible, and no re-treatment was necessary. (D) 10 yrs after internal bleaching. Recurrence of the discoloration is visible, and the patient needed re-treatment. The relapse after 10 yrs, however, was not as severe as the discoloration before bleaching, and the tooth could be re-bleached to a satisfying result. Although intercoronal bleaching does not have—as do most other treatments—indefinite durability, the long-term aesthetic and biological results of this treatment are considered to be of high quality.