The document discusses the causes and management of tooth discoloration, noting that it can be either extrinsic from external stains or intrinsic due to changes in the tooth structure, and treatments include removing surface stains, bleaching techniques, and restorative options like veneers or crowns to mask discoloration. Non-vital bleaching involves removing filling material and gutta percha, sealing off the root canal with GIC, and placing carbamide peroxide gel inside the tooth.