A dead tooth refers to a tooth that has undergone root canal therapy, where the soft inner pulp containing the nerves and blood vessels has been removed due to infection or trauma. A crown can be placed on this type of tooth and is usually highly recommended. A full-coverage dental crown is the standard final restoration following root canal treatment. The crown shields the remaining tooth structure from the forces of chewing, preventing fracture and ensuring the tooth’s long-term survival.
The Structural Necessity of Crowning a Dead Tooth
The removal of the dental pulp during a root canal procedure significantly compromises a tooth’s structural integrity, making a crown necessary for its continued function. Although the tooth remains anchored in the jawbone, it loses the internal source of moisture and nourishment once the pulp is gone. This change in the dentin, the layer beneath the enamel, is thought to increase the tooth’s brittleness over time.
Additionally, the initial decay, trauma, or large filling that necessitated the root canal procedure often means a significant amount of the tooth’s original structure has already been lost. The preparation for the root canal itself involves creating a small access cavity, which further reduces the remaining tooth material. A tooth that has been treated with a root canal is statistically six times more likely to fracture than an untreated tooth if it is not protected with a crown, especially a back tooth that absorbs heavy chewing forces.
A crown acts like a helmet, holding the weakened walls of the tooth together and distributing biting forces evenly across the structure. This full coverage prevents catastrophic types of failure, particularly vertical root fracture, which often leads to the complete loss of the tooth. Without a crown, the remaining tooth structure is susceptible to cusp fracture, where a weakened point breaks off under normal chewing pressure.
Preparing a Non-Vital Tooth for a Crown
Preparing a non-vital tooth for a crown often requires a procedure known as a post and core build-up, which is necessary when insufficient natural tooth material remains to support the crown. The “post” is a small, rod-like structure inserted into the space within the root canal, where the pulp used to be. This process is distinct from the preparation of a healthy tooth, which only involves shaping the outer surface to receive the crown.
The post’s purpose is to retain the “core” material that rebuilds the missing tooth structure, not to reinforce the root against fracture. Dentists remove a portion of the inert filling material, called gutta-percha, from the root canal space to create a channel for the post. Posts are typically made from metal alloys or fiber-reinforced resin, which can be adhesively bonded into the root.
Once the post is cemented, the “core” or build-up material, often composite resin, is packed around the post to replace lost tooth structure. This core material creates a solid foundation, or “stump,” upon which the final crown will be cemented. The rebuilt tooth is then shaped to the precise dimensions required for the crown, ensuring proper fit and margin placement.
Long-Term Maintenance and Risks
A crowned, non-vital tooth is designed for longevity, and with diligent care, the average dental crown can last between 10 to 15 years. However, these restorations require specific attention to maintenance and carry certain long-term risks that differ from those of a healthy tooth. The most common complication is recurrent decay, which can form at the margin where the edge of the crown meets the natural tooth structure.
Since the tooth lacks a nerve, the patient will not feel the pain typically associated with a new cavity, allowing the decay to progress unnoticed until it is severe. Regular dental checkups and X-rays are necessary to monitor the margins for any signs of leakage or decay. Another potential issue is the loosening of the crown, which can occur if the cement seal degrades over time.
The most significant risk specific to a root canal-treated tooth is re-infection of the root canal system, which can lead to a new abscess. This complication may require a second root canal treatment, known as retreatment, or a minor surgical procedure called an apicoectomy. Patients must practice excellent oral hygiene, including flossing around the crown, to protect the crown and the remaining tooth structure from failure.