When a tooth that has undergone root canal treatment (endodontic therapy) turns grey or discolored, it is typically due to changes that occur within the tooth's structure as a result of the treatment. This discoloration is often associated with the loss of vitality in the tooth and changes in its internal tissues.

Composite veneers, also known as dental composite veneers, are a cosmetic dental treatment used to improve the appearance of a person's teeth. They can be a more affordable and less invasive alternative to porcelain veneers.