Internal bleaching lightens discolored teeth that have had root canal treatment by placing a special agent inside the tooth.
Understanding Internal Bleaching
Internal bleaching, also known as non-vital bleaching, is a dental procedure specifically designed to address discoloration from within a tooth. Unlike external bleaching methods that lighten the tooth surface from the outside, internal bleaching targets staining that originates deeper within the tooth structure. This technique is primarily used for teeth that have undergone root canal therapy.
The Core Mechanism
According to the provided reference, the fundamental process involves:
- Placement of a chemical oxidizing agent: A specialized chemical is carefully placed within the coronal portion of a tooth. The "coronal portion" refers to the crown of the tooth, the part visible above the gum line.
- Removal of discoloration: This chemical agent works from the inside out to break down and remove the pigments responsible for the tooth's dark appearance.
Essentially, the oxidizing agent permeates the tooth structure and chemically changes or eliminates the stain molecules trapped within the dentin and enamel layers.
Why is it Used for Root Canal Teeth?
Teeth that have had a root canal often become discolored over time due to various factors, such as:
- Residual necrotic tissue or blood within the tooth's internal structure
- Filling materials used during the root canal procedure
- Lack of blood flow to the tooth after treatment
Since these stains are internal, external bleaching treatments are often ineffective. Internal bleaching provides a direct way to address the discoloration at its source.
Key Steps in the Process
While specific procedures may vary slightly among dental professionals, internal bleaching typically involves the following general steps:
- Isolation: The tooth is isolated from the rest of the mouth using a dental dam to prevent the bleaching agent from contacting the gums or other tissues.
- Access: The dentist re-opens the access cavity created during the root canal treatment.
- Protection: A protective barrier material is placed over the root canal filling material to prevent the bleaching agent from seeping into the root.
- Agent Placement: A chemical oxidizing agent is placed within the coronal portion of the tooth.
- Sealing: The access cavity is temporarily sealed.
- Waiting Period: The patient returns after a few days to a week.
- Evaluation and Repeat (if necessary): The tooth's shade is assessed. If more lightening is needed, the process may be repeated.
- Final Restoration: Once the desired shade is achieved, the bleaching agent is removed, and the tooth is permanently sealed with a filling or crown.
Mechanism Summary
| Step | Location | Action |
|---|---|---|
| Agent Placement | Coronal portion of the tooth | Chemical oxidizing agent is placed |
| Bleaching Process | Within the tooth structure | Oxidizing agent breaks down stain molecules |
| Result | Visible tooth crown | Removes tooth discoloration |
Internal bleaching offers a targeted solution for improving the appearance of a single, discolored tooth that has undergone root canal therapy, helping to restore a more uniform smile.
