Indications for Internal Bleaching

Internal bleaching is indicated for teeth exhibiting discoloration due to:
1. Endodontic treatment.
2. Traumatic changes (e.g., internal bleeding following trauma).
3. Natural aging of the tooth.
4. Residual discoloration caused by filling materials or medications.

Steps of Internal Bleaching

1. Tooth Preparation
• High-quality root canal treatment is the foundational step. The canal must be hermetically sealed, with no signs of periapical infection.
• Removal of the existing restoration from the access cavity and thorough cleaning of the pulp chamber.
• Part of the root canal filling is removed apically from the gingival margin to a depth of approximately 1 mm.
• Sealing the root canal with glass ionomer cement or better composite material to prevent bleaching agent penetration into the root system.

2. Application of the Bleaching Agent
• A bleaching agent, such as 10% carbamide peroxide or another suitable product, is applied into the pulp chamber.
• Sealing the access cavity is performed using adhesive techniques with composite material in a color distinct from the tooth to ensure easy identification.

3. Monitoring and Reapplication
• The patient monitors the bleaching results daily
• If the tooth significantly lightens and approaches the color of the adjacent teeth, or becomes slightly over-bleached, the patient is instructed to call the dentist and schedule a follow-up appointment.
• Follow-up visits are generally planned every 5–7 days to evaluate the effect and reapply the bleaching agent if needed.

4. Completion of Bleaching
• Once the desired shade is achieved, the composite restoration is removed, and the pulp chamber is cleaned of any bleaching agent residue.
• Subsequently, it is necessary to wait 14 days before final restoration to allow the diffusion of residual oxygen released during the bleaching process. This oxygen could otherwise inhibit the polymerization of adhesive systems and weaken the bond between the composite and the tooth structure. After this period, the conditions for final restoration are optimal.
• After this period, the internal walls of the pulp chamber are etched, adhesive systems are applied, and the cavity is definitively restored with a composite material matching the tooth color.

Risk of External Root Resorption
• Emphasis is placed on high-quality and hermetic sealing of the root canal to prevent bleaching agent penetration, which could lead to resorption.
• The seal must have the correct height and concave shape, respecting the contour of the gingiva and bone. Proper depth and precise shaping of the root canal seal are essential.
• Using appropriate concentrations of bleaching agents minimizes the risk of damage.

Conclusion
• Internal bleaching is an effective method for restoring the esthetic appearance of non-vital teeth.
• Key steps include precise tooth preparation, high-quality hermetic sealing of the root canal, and diligent monitoring of the results.
• By adhering to all protocols and maintaining strict control, excellent and long-lasting results can be achieved.