Because the tooth has already been root canal treated, Dr. Velkovski has access to the inner chamber through the existing access point. He places a professional-grade bleaching agent inside the tooth and seals it temporarily. The bleaching agent works from the inside over several days. At a follow-up appointment, the shade is evaluated, the process is repeated if needed, and when the desired result is achieved, the access point is permanently sealed. Most cases are resolved in two to three appointments.