Tooth discolouration usually happens as a result of traumatic dental injuries, pulp necrosis, pulp tissue remnants after endodontic therapy, internal resorption, restorative and endodontic material, etc. It can be effectively and safely corrected with walking bleach technique (a.k.a. internal bleaching).  This technique is a conservative alternative to a more invasive aesthetic treatment such as placement of crowns or veneers.

Requirements for the proper technique:

1. recording the initial shade with a shade guide
2. performing adequate endodontic treatment under rubber dam isolation
3. removing all obturation/restorative material to the level below CEJ
4. placing a barrier (GIC, composite, IRM, etc.) over the obturation material to the level 1mm incisal to external probing of the gingival attachment
5. packing sodium perborate (mixed with water or anesthetic solution) in the chamber
6. sealing the access cavity with GIC or composite
7. following up in 1 week to determine the final result (the bleaching procedure can be repeated 3-4 times max)
8. removing the bleaching agent and restoring the access cavity permanently
9. recording the final shade

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