A dead tooth is one that has lost its living tissues within the pulp chamber. This condition frequently occurs following severe dental trauma or as a result of root canal therapy, which removes the infected or necrotic pulp. The color change is caused by the breakdown of blood products, such as hemoglobin, and necrotic tissue remnants that release pigments like iron. These degradation products penetrate the microscopic tubules of the dentin layer, resulting in a distinct yellow, gray, or sometimes black discoloration. This staining originates deep inside the tooth structure, not on the outer enamel surface.
Why Standard Whitening Does Not Work
Traditional external teeth whitening methods, such as over-the-counter strips or custom bleaching trays, are designed to address surface stains. These products rely on peroxide agents penetrating the outer enamel to reach and break down chromogens in the superficial dentin. This process works effectively for generalized yellowing or external stains affecting a vital tooth.
The deep intrinsic discoloration of a non-vital tooth presents a unique challenge that external agents cannot overcome. The source of the dark staining is sealed within the former pulp chamber. Because the stain is locked in this internal space, chemicals applied to the tooth’s exterior cannot reach the concentration necessary to reverse the deep pigmentation. Consequently, a different approach is necessary to treat this internal discoloration.
The Internal Bleaching Procedure
The solution to a discolored non-vital tooth is a specialized technique known as internal bleaching, often referred to as the “walking bleach” method. This procedure involves placing a bleaching agent directly inside the tooth, where the stain originates. The process begins after the tooth has been confirmed to have a successful root canal filling, which ensures the root is sealed.
The dentist first creates a small access cavity on the back of the tooth to enter the pulp chamber. Any remnants of the old filling material and stained dentin are removed from the coronal portion of the tooth. A protective barrier, typically a two-millimeter layer of glass ionomer or flowable composite, is then placed over the root canal filling material. This barrier prevents the bleaching agent from leaking down into the root and surrounding gum tissue.
Next, the bleaching agent is inserted into the cleaned-out chamber, where it acts directly on the stains. The most common agent used is sodium perborate, often mixed with distilled water or low-concentration hydrogen peroxide to form a thick paste. The tooth is then sealed with a temporary filling, allowing the bleaching material to work over several days.
The patient returns after about one week for the dentist to assess the shade change. If the desired lightness has not been achieved, the old mixture is removed, a fresh batch of the bleaching agent is placed inside, and the tooth is sealed again. This cycle is repeated until the tooth matches the color of the adjacent natural teeth. A risk associated with internal bleaching is external cervical root resorption, a complication where the root structure is damaged near the gum line.
Other Long-Term Cosmetic Restoration Options
While internal bleaching may not be suitable for every case, such as when the tooth is structurally compromised or the discoloration is too severe, more durable cosmetic restorations offer a better long-term solution. Two primary alternatives are porcelain veneers and dental crowns, each addressing different levels of damage.
Veneers are thin, custom-made shells of porcelain that are bonded to the front surface of the tooth. This option is highly effective for masking severe discoloration that is resistant to bleaching. Veneers require only minimal removal of the external enamel, making them a less invasive option than a full crown.
A dental crown is a tooth-shaped cap that covers the entire visible portion of the tooth. Crowns are recommended when the non-vital tooth has significant structural damage, a large existing filling, or is weakened from the root canal procedure itself. A crown provides complete protection and structural reinforcement, in addition to restoring the tooth’s appearance.
Both veneers and crowns offer an esthetic result, especially for teeth that are heavily damaged. While internal bleaching is the most cost-effective and minimally invasive initial treatment, these restorations provide superior strength and longevity for severely compromised teeth.